#include "algorithm.hpp"
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
// Blog: http://blog.csdn.net/fengbingchun/article/details/78034969
// reference: http://www.cplusplus.com/reference/algorithm/
namespace algorithm_ {
///////////////////////////////////////
static bool myfunction(int i, int j) { return (i == j); }
static bool comp_case_insensitive(char c1, char c2) { return (std::tolower(c1) == std::tolower(c2)); }
static bool IsOdd(int i) { return ((i % 2) == 1); }
int test_algorithm_find()
{
{
int myints[] = { 5, 20, 5, 30, 30, 20, 10, 10, 20 };
std::vector myvector(myints, myints + 8);
std::vector::iterator it;
// using default comparison:
it = std::adjacent_find(myvector.begin(), myvector.end());
if (it != myvector.end())
std::cout << "the first pair of repeated elements are: " << *it << '\n'; // 30
//using predicate comparison:
it = std::adjacent_find(++it, myvector.end(), myfunction);
if (it != myvector.end())
std::cout << "the second pair of repeated elements are: " << *it << '\n'; // 10
}
{
// using std::find with array and pointer:
int myints[] = { 10, 20, 30, 40 };
int * p;
p = std::find(myints, myints + 4, 30);
if (p != myints + 4)
std::cout << "Element found in myints: " << *p << '\n'; // 30
else
std::cout << "Element not found in myints\n";
// using std::find with vector and iterator:
std::vector myvector(myints, myints + 4);
std::vector::iterator it;
it = std::find(myvector.begin(), myvector.end(), 30);
if (it != myvector.end())
std::cout << "Element found in myvector: " << *it << '\n'; // 30
else
std::cout << "Element not found in myvector\n";
}
{
int myints[] = { 1, 2, 3, 4, 5, 1, 2, 3, 4, 5 };
std::vector haystack(myints, myints + 10);
int needle1[] = { 1, 2, 3 };
// using default comparison:
std::vector::iterator it;
it = std::find_end(haystack.begin(), haystack.end(), needle1, needle1 + 3);
if (it != haystack.end())
std::cout << "needle1 last found at position " << (it - haystack.begin()) << '\n'; // 5
int needle2[] = { 4, 5, 1 };
// using predicate comparison:
it = std::find_end(haystack.begin(), haystack.end(), needle2, needle2 + 3, myfunction);
if (it != haystack.end())
std::cout << "needle2 last found at position " << (it - haystack.begin()) << '\n'; // 3
}
{
int mychars[] = { 'a', 'b', 'c', 'A', 'B', 'C' };
std::vector haystack(mychars, mychars + 6);
std::vector::iterator it;
int needle[] = { 'A', 'B', 'C' };
// using default comparison:
it = find_first_of(haystack.begin(), haystack.end(), needle, needle + 3);
if (it != haystack.end())
std::cout << "The first match is: " << *it << '\n'; // A
// using predicate comparison:
it = find_first_of(haystack.begin(), haystack.end(), needle, needle + 3, comp_case_insensitive);
if (it != haystack.end())
std::cout << "The first match is: " << *it << '\n'; // a
}
{
std::vector myvector;
myvector.push_back(10);
myvector.push_back(25);
myvector.push_back(40);
myvector.push_back(55);
std::vector::iterator it = std::find_if(myvector.begin(), myvector.end(), IsOdd);
std::cout << "The first odd value is " << *it << '\n'; // 25
}
{
std::array foo = { 1, 2, 3, 4, 5 };
std::array::iterator it = std::find_if_not(foo.begin(), foo.end(), [](int i){return i % 2; });
std::cout << "The first even value is " << *it << '\n'; // 2
}
return 0;
}
////////////////////////////////////////////
int test_algorithm_all_of()
{
{
std::array foo = { 3, 5, 7, 11, 13, 17, 19, 23 };
if (std::all_of(foo.begin(), foo.end(), [](int i){return i % 2; }))
std::cout << "All the elements are odd numbers.\n"; // All the elements are odd numbers
}
{
std::array foo = { 0, 1, -1, 3, -3, 5, -5 };
if (std::any_of(foo.begin(), foo.end(), [](int i){return i<0; }))
std::cout << "There are negative elements in the range.\n"; // There are negative elements in the range
}
{
std::array foo = { 1, 2, 4, 8, 16, 32, 64, 128 };
if (std::none_of(foo.begin(), foo.end(), [](int i){return i<0; }))
std::cout << "There are no negative elements in the range.\n"; // There are no negative elements in the range
}
return 0;
}
////////////////////////////////////////////////
static bool myfunction2(int i, int j) { return (i v(myints, myints + 9);
// using default comparison:
std::sort(v.begin(), v.end());
std::cout << "looking for a 3... ";
if (std::binary_search(v.begin(), v.end(), 3)) std::cout << "found!\n"; // found!
else std::cout << "not found.\n";
// using myfunction as comp:
std::sort(v.begin(), v.end(), myfunction2);
std::cout << "looking for a 6... ";
if (std::binary_search(v.begin(), v.end(), 6, myfunction2)) std::cout << "found!\n";
else std::cout << "not found.\n"; // not found.
}
{
std::vector haystack;
// set some values: haystack: 10 20 30 40 50 60 70 80 90
for (int i = 1; i<10; i++) haystack.push_back(i * 10);
// using default comparison:
int needle1[] = { 40, 50, 60, 70 };
std::vector::iterator it;
it = std::search(haystack.begin(), haystack.end(), needle1, needle1 + 4);
if (it != haystack.end())
std::cout << "needle1 found at position " << (it - haystack.begin()) << '\n'; // 3
else
std::cout << "needle1 not found\n";
// using predicate comparison:
int needle2[] = { 20, 30, 50 };
it = std::search(haystack.begin(), haystack.end(), needle2, needle2 + 3, mypredicate);
if (it != haystack.end())
std::cout << "needle2 found at position " << (it - haystack.begin()) << '\n';
else
std::cout << "needle2 not found\n"; // needle2 not found
}
{
int myints[] = { 10, 20, 30, 30, 20, 10, 10, 20 };
std::vector myvector(myints, myints + 8);
std::vector::iterator it;
// using default comparison:
it = std::search_n(myvector.begin(), myvector.end(), 2, 30);
if (it != myvector.end())
std::cout << "two 30s found at position " << (it - myvector.begin()) << '\n'; // 2
else
std::cout << "match not found\n";
// using predicate comparison:
it = std::search_n(myvector.begin(), myvector.end(), 2, 10, mypredicate);
if (it != myvector.end())
std::cout << "two 10s found at position " << int(it - myvector.begin()) << '\n'; // 5
else
std::cout << "match not found\n";
}
return 0;
}
//////////////////////////////////////////////
int test_algorithm_copy()
{
{
int myints[] = { 10, 20, 30, 40, 50, 60, 70 };
std::vector myvector(7);
std::copy(myints, myints + 7, myvector.begin());
std::cout << "myvector contains:";
for (std::vector::iterator it = myvector.begin(); it != myvector.end(); ++it)
std::cout << ' ' << *it; // 10 20 30 40 50 60 70
std::cout << '\n';
}
{
std::vector myvector;
// set some values:
for (int i = 1; i <= 5; i++)
myvector.push_back(i * 10); // myvector: 10 20 30 40 50
myvector.resize(myvector.size() + 3); // allocate space for 3 more elements
std::copy_backward(myvector.begin(), myvector.begin() + 5, myvector.end());
std::cout << "myvector contains:";
for (std::vector::iterator it = myvector.begin(); it != myvector.end(); ++it)
std::cout << ' ' << *it; // 10 20 30 10 20 30 40 50
std::cout << '\n';
}
{
std::vector foo = { 25, 15, 5, -5, -15 };
std::vector bar(foo.size());
// copy only positive numbers:
auto it = std::copy_if(foo.begin(), foo.end(), bar.begin(), [](int i){return !(i<0); });
bar.resize(std::distance(bar.begin(), it)); // shrink container to new size
std::cout << "bar contains:";
for (int& x : bar) std::cout << ' ' << x; // 25 15 5
std::cout << '\n';
}
{
int myints[] = { 10, 20, 30, 40, 50, 60, 70 };
std::vector myvector;
myvector.resize(7); // allocate space for 7 elements
std::copy_n(myints, 7, myvector.begin());
std::cout << "myvector contains:";
for (std::vector::iterator it = myvector.begin(); it != myvector.end(); ++it)
std::cout << ' ' << *it; // 10 20 30 40 50 60 70
std::cout << '\n';
}
return 0;
}
///////////////////////////////////////////////
int test_algorithm_count()
{
{
// counting elements in array:
int myints[] = { 10, 20, 30, 30, 20, 10, 10, 20 }; // 8 elements
int mycount = std::count(myints, myints + 8, 10);
std::cout << "10 appears " << mycount << " times.\n"; // 3
// counting elements in container:
std::vector myvector(myints, myints + 8);
mycount = std::count(myvector.begin(), myvector.end(), 20);
std::cout << "20 appears " << mycount << " times.\n"; // 3
}
{
std::vector myvector;
for (int i = 1; i<10; i++) myvector.push_back(i); // myvector: 1 2 3 4 5 6 7 8 9
int mycount = count_if(myvector.begin(), myvector.end(), IsOdd);
std::cout << "myvector contains " << mycount << " odd values.\n"; // 5
}
return 0;
}
//////////////////////////////////////////
static bool mygreater(int i, int j) { return (i>j); }
int test_algorithm_equal()
{
{
int myints[] = { 20, 40, 60, 80, 100 }; // myints: 20 40 60 80 100
std::vectormyvector(myints, myints + 5); // myvector: 20 40 60 80 100
// using default comparison:
if (std::equal(myvector.begin(), myvector.end(), myints))
std::cout << "The contents of both sequences are equal.\n"; // equal
else
std::cout << "The contents of both sequences differ.\n";
myvector[3] = 81; // myvector: 20 40 60 81 100
// using predicate comparison:
if (std::equal(myvector.begin(), myvector.end(), myints, mypredicate))
std::cout << "The contents of both sequences are equal.\n";
else
std::cout << "The contents of both sequences differ.\n"; // differ
}
{
int myints[] = { 10, 20, 30, 30, 20, 10, 10, 20 };
std::vector v(myints, myints + 8); // 10 20 30 30 20 10 10 20
std::pair::iterator, std::vector::iterator> bounds;
// using default comparison:
std::sort(v.begin(), v.end()); // 10 10 10 20 20 20 30 30
bounds = std::equal_range(v.begin(), v.end(), 20); // ^ ^
std::cout << "bounds at positions " << (bounds.first - v.begin()); // 3
std::cout << " and " << (bounds.second - v.begin()) << '\n'; // 6
// using "mygreater" as comp:
std::sort(v.begin(), v.end(), mygreater); // 30 30 20 20 20 10 10 10
bounds = std::equal_range(v.begin(), v.end(), 20, mygreater); // ^ ^
std::cout << "bounds at positions " << (bounds.first - v.begin()); // 2
std::cout << " and " << (bounds.second - v.begin()) << '\n'; // 5
}
{
int myints[] = { 10, 20, 30, 30, 20, 10, 10, 20 };
std::vector v(myints, myints + 8); // 10 20 30 30 20 10 10 20
std::sort(v.begin(), v.end()); // 10 10 10 20 20 20 30 30
std::vector::iterator low, up;
low = std::lower_bound(v.begin(), v.end(), 20);
up = std::upper_bound(v.begin(), v.end(), 20);
std::cout << "lower_bound at position " << (low - v.begin()) << '\n'; // 3
std::cout << "upper_bound at position " << (up - v.begin()) << '\n'; // 6
}
return 0;
}
//////////////////////////////////////////
int test_algorithm_fill()
{
{
std::vector myvector(8); // myvector: 0 0 0 0 0 0 0 0
std::fill(myvector.begin(), myvector.begin() + 4, 5); // myvector: 5 5 5 5 0 0 0 0
std::fill(myvector.begin() + 3, myvector.end() - 2, 8); // myvector: 5 5 5 8 8 8 0 0
std::cout << "myvector contains:";
for (std::vector::iterator it = myvector.begin(); it != myvector.end(); ++it)
std::cout << ' ' << *it; // 5 5 5 8 8 8 0 0
std::cout << '\n';
}
{
std::vector myvector(8, 10); // myvector: 10 10 10 10 10 10 10 10
std::fill_n(myvector.begin(), 4, 20); // myvector: 20 20 20 20 10 10 10 10
std::fill_n(myvector.begin() + 3, 3, 33); // myvector: 20 20 20 33 33 33 10 10
std::cout << "myvector contains:";
for (std::vector::iterator it = myvector.begin(); it != myvector.end(); ++it)
std::cout << ' ' << *it; // 20 20 20 33 33 33 10 10
std::cout << '\n';
}
return 0;
}
///////////////////////////////////////////
void myfunction3(int i) { // function:
std::cout << ' ' << i;
}
struct myclass { // function object type:
void operator() (int i) { std::cout << ' ' << i; }
} myobject;
int test_algorithm_for_each()
{
std::vector myvector;
myvector.push_back(10);
myvector.push_back(20);
myvector.push_back(30);
std::cout << "myvector contains:";
for_each(myvector.begin(), myvector.end(), myfunction3); // 10 20 30
std::cout << '\n';
// or:
std::cout << "myvector contains:";
for_each(myvector.begin(), myvector.end(), myobject); // 10 20 30
std::cout << '\n';
return 0;
}
////////////////////////////////////////////////
// function generator:
int RandomNumber() { return (std::rand() % 100); }
// class generator:
struct c_unique {
int current;
c_unique() { current = 0; }
int operator()() { return ++current; }
} UniqueNumber;
int current = 0;
int UniqueNumber2() { return ++current; }
int test_algorithm_generate()
{
{
std::srand(unsigned(std::time(0)));
std::vector myvector(8);
std::generate(myvector.begin(), myvector.end(), RandomNumber);
std::cout << "myvector contains:";
for (std::vector::iterator it = myvector.begin(); it != myvector.end(); ++it)
std::cout << ' ' << *it;
std::cout << '\n';
std::generate(myvector.begin(), myvector.end(), UniqueNumber);
std::cout << "myvector contains:";
for (std::vector::iterator it = myvector.begin(); it != myvector.end(); ++it)
std::cout << ' ' << *it; // 1 2 3 4 5 6 7 8
std::cout << '\n';
}
{
int myarray[9];
std::generate_n(myarray, 9, UniqueNumber2);
std::cout << "myarray contains:";
for (int i = 0; i<9; ++i)
std::cout << ' ' << myarray[i]; // 1 2 3 4 5 6 7 8 9
std::cout << '\n';
}
return 0;
}
////////////////////////////////////////////////
int test_algorithm_includes()
{
int container[] = { 5, 10, 15, 20, 25, 30, 35, 40, 45, 50 };
int continent[] = { 40, 30, 20, 10 };
std::sort(container, container + 10);
std::sort(continent, continent + 4);
// using default comparison:
if (std::includes(container, container + 10, continent, continent + 4))
std::cout << "container includes continent!\n"; // container includes continent
// using myfunction as comp:
if (std::includes(container, container + 10, continent, continent + 4, myfunction2))
std::cout << "container includes continent!\n"; // container includes continent
return 0;
}
///////////////////////////////////////////////////////////
int test_algorithm_merge()
{
{
int first[] = { 5, 10, 15, 20, 25 };
int second[] = { 50, 40, 30, 20, 10 };
std::vector v(10);
std::vector::iterator it;
std::sort(first, first + 5);
std::sort(second, second + 5);
it = std::copy(first, first + 5, v.begin());
std::copy(second, second + 5, it);
std::inplace_merge(v.begin(), v.begin() + 5, v.end());
std::cout << "The resulting vector contains:";
for (it = v.begin(); it != v.end(); ++it)
std::cout << ' ' << *it; // 5 10 10 15 20 20 25 30 40 50
std::cout << '\n';
}
{
int first[] = { 5, 10, 15, 20, 25 };
int second[] = { 50, 40, 30, 20, 10 };
std::vector v(10);
std::sort(first, first + 5);
std::sort(second, second + 5);
std::merge(first, first + 5, second, second + 5, v.begin());
std::cout << "The resulting vector contains:";
for (std::vector::iterator it = v.begin(); it != v.end(); ++it)
std::cout << ' ' << *it; // 5 10 10 15 20 20 25 30 40 50
std::cout << '\n';
}
return 0;
}
////////////////////////////////////////
int test_algorithm_heap()
{
{
std::vector foo{ 9, 5, 2, 6, 4, 1, 3, 8, 7 };
if (!std::is_heap(foo.begin(), foo.end()))
std::make_heap(foo.begin(), foo.end());
std::cout << "Popping out elements:";
while (!foo.empty()) {
std::pop_heap(foo.begin(), foo.end()); // moves largest element to back
std::cout << ' ' << foo.back(); // prints back // 9 8 7 6 5 4 3 2 1
foo.pop_back(); // pops element out of container
}
std::cout << '\n';
}
{
std::vector foo{ 2, 6, 9, 3, 8, 4, 5, 1, 7 };
std::sort(foo.begin(), foo.end());
std::reverse(foo.begin(), foo.end());
auto last = std::is_heap_until(foo.begin(), foo.end());
std::cout << "The " << (last - foo.begin()) << " first elements are a valid heap:"; // 9
for (auto it = foo.begin(); it != last; ++it)
std::cout << ' ' << *it; // 9 8 7 6 5 4 3 2 1
std::cout << '\n';
}
{
int myints[] = { 10, 20, 30, 5, 15 };
std::vector v(myints, myints + 5);
std::make_heap(v.begin(), v.end());
std::cout << "initial max heap : " << v.front() << '\n'; // 30
std::pop_heap(v.begin(), v.end()); v.pop_back();
std::cout << "max heap after pop : " << v.front() << '\n'; // 20
v.push_back(99); std::push_heap(v.begin(), v.end());
std::cout << "max heap after push: " << v.front() << '\n'; // 99
std::sort_heap(v.begin(), v.end());
std::cout << "final sorted range :";
for (unsigned i = 0; i foo{ 1, 2, 3, 4, 5, 6, 7 };
// print contents:
std::cout << "foo:"; for (int& x : foo) std::cout << ' ' << x;
if (std::is_partitioned(foo.begin(), foo.end(), IsOdd))
std::cout << " (partitioned)\n";
else
std::cout << " (not partitioned)\n"; // not partitioned
// partition array:
std::partition(foo.begin(), foo.end(), IsOdd);
// print contents again:
std::cout << "foo:"; for (int& x : foo) std::cout << ' ' << x; // 1 7 3 5 4 6 2
if (std::is_partitioned(foo.begin(), foo.end(), IsOdd))
std::cout << " (partitioned)\n"; // partitioned
else
std::cout << " (not partitioned)\n";
}
{
std::vector myvector;
// set some values:
for (int i = 1; i<10; ++i) myvector.push_back(i); // 1 2 3 4 5 6 7 8 9
std::vector::iterator bound;
bound = std::partition(myvector.begin(), myvector.end(), IsOdd);
// print out content:
std::cout << "odd elements:";
for (std::vector::iterator it = myvector.begin(); it != bound; ++it)
std::cout << ' ' << *it; // 1 9 3 7 5
std::cout << '\n';
std::cout << "even elements:";
for (std::vector::iterator it = bound; it != myvector.end(); ++it)
std::cout << ' ' << *it; // 6 4 8 2
std::cout << '\n';
}
{
std::vector foo{ 1, 2, 3, 4, 5, 6, 7, 8, 9 };
std::vector odd, even;
// resize vectors to proper size:
unsigned n = std::count_if(foo.begin(), foo.end(), IsOdd);
odd.resize(n); even.resize(foo.size() - n);
// partition:
std::partition_copy(foo.begin(), foo.end(), odd.begin(), even.begin(), IsOdd);
// print contents:
std::cout << "odd: "; for (int& x : odd) std::cout << ' ' << x; std::cout << '\n'; // 1 3 5 7 9
std::cout << "even: "; for (int& x : even) std::cout << ' ' << x; std::cout << '\n'; // 2 4 6 8
}
{
std::vector foo{ 1, 2, 3, 4, 5, 6, 7, 8, 9 };
std::vector odd;
std::partition(foo.begin(), foo.end(), IsOdd);
auto it = std::partition_point(foo.begin(), foo.end(), IsOdd);
odd.assign(foo.begin(), it);
// print contents of odd:
std::cout << "odd:";
for (int& x : odd) std::cout << ' ' << x; // 1 9 3 7 5
std::cout << '\n';
}
{
std::vector myvector;
// set some values:
for (int i = 1; i<10; ++i) myvector.push_back(i); // 1 2 3 4 5 6 7 8 9
std::vector::iterator bound;
bound = std::stable_partition(myvector.begin(), myvector.end(), IsOdd);
// print out content:
std::cout << "odd elements:";
for (std::vector::iterator it = myvector.begin(); it != bound; ++it)
std::cout << ' ' << *it; // 1 3 5 7 9
std::cout << '\n';
std::cout << "even elements:";
for (std::vector::iterator it = bound; it != myvector.end(); ++it)
std::cout << ' ' << *it; // 2 4 6 8
std::cout << '\n';
}
return 0;
}
//////////////////////////////////////
int test_algorithm_permutation()
{
{
std::array foo = { 1, 2, 3, 4, 5 };
std::array bar = { 3, 1, 4, 5, 2 };
if (std::is_permutation(foo.begin(), foo.end(), bar.begin()))
std::cout << "foo and bar contain the same elements.\n"; // foo and bar contain the same elements
}
{
int myints[] = { 1, 2, 3 };
std::sort(myints, myints + 3);
std::cout << "The 3! possible permutations with 3 elements:\n";
do {
std::cout << myints[0] << ' ' << myints[1] << ' ' << myints[2] << '\n';
} while (std::next_permutation(myints, myints + 3));
std::cout << "After loop: " << myints[0] << ' ' << myints[1] << ' ' << myints[2] << '\n'; // 1 2 3
}
{
int myints[] = { 1, 2, 3 };
std::sort(myints, myints + 3);
std::reverse(myints, myints + 3);
std::cout << "The 3! possible permutations with 3 elements:\n";
do {
std::cout << myints[0] << ' ' << myints[1] << ' ' << myints[2] << '\n';
} while (std::prev_permutation(myints, myints + 3));
std::cout << "After loop: " << myints[0] << ' ' << myints[1] << ' ' << myints[2] << '\n'; // 3 2 1
}
return 0;
}
/////////////////////////////////////////////
struct myclass2 {
bool operator() (int i, int j) { return (i foo{ 2, 4, 1, 3 };
do {
// try a new permutation:
std::prev_permutation(foo.begin(), foo.end());
// print range:
std::cout << "foo:";
for (int& x : foo) std::cout << ' ' << x;
std::cout << '\n';
} while (!std::is_sorted(foo.begin(), foo.end()));
std::cout << "the range is sorted!\n";
}
{
std::array foo{ 2, 4, 1, 3 };
std::array::iterator it;
do {
// try a new permutation:
std::prev_permutation(foo.begin(), foo.end());
// print range:
std::cout << "foo:";
for (int& x : foo) std::cout << ' ' << x;
it = std::is_sorted_until(foo.begin(), foo.end());
std::cout << " (" << (it - foo.begin()) << " elements sorted)\n";
} while (it != foo.end());
std::cout << "the range is sorted!\n";
}
{
std::vector myvector;
// set some values:
for (int i = 1; i<10; i++) myvector.push_back(i); // 1 2 3 4 5 6 7 8 9
std::random_shuffle(myvector.begin(), myvector.end());
// using default comparison (operator <):
std::nth_element(myvector.begin(), myvector.begin() + 5, myvector.end());
// using function as comp
std::nth_element(myvector.begin(), myvector.begin() + 5, myvector.end(), myfunction2);
// print out content:
std::cout << "myvector contains:";
for (std::vector::iterator it = myvector.begin(); it != myvector.end(); ++it)
std::cout << ' ' << *it; // 1 2 3 4 5 6 7 8 9
std::cout << '\n';
}
{
int myints[] = { 9, 8, 7, 6, 5, 4, 3, 2, 1 };
std::vector myvector(myints, myints + 9);
// using default comparison (operator <):
std::partial_sort(myvector.begin(), myvector.begin() + 5, myvector.end());
// using function as comp
std::partial_sort(myvector.begin(), myvector.begin() + 5, myvector.end(), myfunction2);
// print out content:
std::cout << "myvector contains:";
for (std::vector::iterator it = myvector.begin(); it != myvector.end(); ++it)
std::cout << ' ' << *it; // 1 2 3 4 5 9 8 7 6
std::cout << '\n';
}
{
int myints[] = { 9, 8, 7, 6, 5, 4, 3, 2, 1 };
std::vector myvector(5);
// using default comparison (operator <):
std::partial_sort_copy(myints, myints + 9, myvector.begin(), myvector.end());
// using function as comp
std::partial_sort_copy(myints, myints + 9, myvector.begin(), myvector.end(), myfunction2);
// print out content:
std::cout << "myvector contains:";
for (std::vector::iterator it = myvector.begin(); it != myvector.end(); ++it)
std::cout << ' ' << *it; // 1 2 3 4 5
std::cout << '\n';
}
{
int myints[] = { 32, 71, 12, 45, 26, 80, 53, 33 };
std::vector myvector(myints, myints + 8); // 32 71 12 45 26 80 53 33
// using default comparison (operator <):
std::sort(myvector.begin(), myvector.begin() + 4); //(12 32 45 71)26 80 53 33
// using function as comp
std::sort(myvector.begin() + 4, myvector.end(), myfunction2); // 12 32 45 71(26 33 53 80)
// using object as comp
std::sort(myvector.begin(), myvector.end(), myobject2); //(12 26 32 33 45 53 71 80)
// print out content:
std::cout << "myvector contains:";
for (std::vector::iterator it = myvector.begin(); it != myvector.end(); ++it)
std::cout << ' ' << *it; // 12 26 32 33 45 53 71 80
std::cout << '\n';
}
{
double mydoubles[] = { 3.14, 1.41, 2.72, 4.67, 1.73, 1.32, 1.62, 2.58 };
std::vector myvector;
myvector.assign(mydoubles, mydoubles + 8);
std::cout << "using default comparison:";
std::stable_sort(myvector.begin(), myvector.end());
for (std::vector::iterator it = myvector.begin(); it != myvector.end(); ++it)
std::cout << ' ' << *it; // 1.32 1.41 1.62 1.73 2.58 2.72 3.14 4.67
std::cout << '\n';
myvector.assign(mydoubles, mydoubles + 8);
std::cout << "using 'compare_as_ints' :";
std::stable_sort(myvector.begin(), myvector.end(), compare_as_ints);
for (std::vector::iterator it = myvector.begin(); it != myvector.end(); ++it)
std::cout << ' ' << *it; // 1.41 1.73 1.32 1.62 2.72 2.58 3.14 4.67
std::cout << '\n';
}
return 0;
}
////////////////////////////////////////////////////
int test_algorithm_swap()
{
{
int myints[] = { 10, 20, 30, 40, 50 }; // myints: 10 20 30 40 50
std::vector myvector(4, 99); // myvector: 99 99 99 99
std::iter_swap(myints, myvector.begin()); // myints: [99] 20 30 40 50
// myvector: [10] 99 99 99
std::iter_swap(myints + 3, myvector.begin() + 2); // myints: 99 20 30 [99] 50
// myvector: 10 99 [40] 99
std::cout << "myvector contains:";
for (std::vector::iterator it = myvector.begin(); it != myvector.end(); ++it)
std::cout << ' ' << *it; // 10 99 40 99
std::cout << '\n';
}
{
int x = 10, y = 20; // x:10 y:20
std::swap(x, y); // x:20 y:10
std::vector foo(4, x), bar(6, y); // foo:4x20 bar:6x10
std::swap(foo, bar); // foo:6x10 bar:4x20
std::cout << "foo contains:";
for (std::vector::iterator it = foo.begin(); it != foo.end(); ++it)
std::cout << ' ' << *it; // 10 10 10 10 10 10
std::cout << '\n';
}
{
std::vector foo(5, 10); // foo: 10 10 10 10 10
std::vector bar(5, 33); // bar: 33 33 33 33 33
std::swap_ranges(foo.begin() + 1, foo.end() - 1, bar.begin());
// print out results of swap:
std::cout << "foo contains:";
for (std::vector::iterator it = foo.begin(); it != foo.end(); ++it)
std::cout << ' ' << *it; // 10 33 33 33 10
std::cout << '\n';
std::cout << "bar contains:";
for (std::vector::iterator it = bar.begin(); it != bar.end(); ++it)
std::cout << ' ' << *it; // 10 10 10 33 33
std::cout << '\n';
}
return 0;
}
///////////////////////////////////////////////
static bool mycomp(char c1, char c2) { return std::tolower(c1) foo{ 3, 7, 2, 9, 5, 8, 6 };
auto result = std::minmax_element(foo.begin(), foo.end());
// print result:
std::cout << "min is " << *result.first; // 2
std::cout << ", at position " << (result.first - foo.begin()) << '\n'; // 2
std::cout << "max is " << *result.second; // 9
std::cout << ", at position " << (result.second - foo.begin()) << '\n'; // 3
}
return 0;
}
///////////////////////////////////////////
int test_algorithm_mismatch()
{
std::vector myvector;
for (int i = 1; i<6; i++) myvector.push_back(i * 10); // myvector: 10 20 30 40 50
int myints[] = { 10, 20, 80, 320, 1024 }; // myints: 10 20 80 320 1024
std::pair::iterator, int*> mypair;
// using default comparison:
mypair = std::mismatch(myvector.begin(), myvector.end(), myints);
std::cout << "First mismatching elements: " << *mypair.first; // 30
std::cout << " and " << *mypair.second << '\n'; // 80
++mypair.first; ++mypair.second;
// using predicate comparison:
mypair = std::mismatch(mypair.first, myvector.end(), mypair.second, mypredicate);
std::cout << "Second mismatching elements: " << *mypair.first; // 40
std::cout << " and " << *mypair.second << '\n'; // 320
return 0;
}
//////////////////////////////////////////
/* The behavior of std::move_backward template is equivalent to:
template
BidirectionalIterator2 move_backward ( BidirectionalIterator1 first,
BidirectionalIterator1 last,
BidirectionalIterator2 result )
{
while (last!=first) *(--result) = std::move(*(--last));
return result;
}
*/
int test_algorithm_move()
{
{
std::vector foo = { "air", "water", "fire", "earth" };
std::vector bar(4);
// moving ranges:
std::cout << "Moving ranges...\n";
std::move(foo.begin(), foo.begin() + 4, bar.begin());
std::cout << "foo contains " << foo.size() << " elements:";// 4
std::cout << " (each in an unspecified but valid state)";
std::cout << '\n';
std::cout << "bar contains " << bar.size() << " elements:"; // 4
for (std::string& x : bar) std::cout << " [" << x << "]"; // [air] [water] [fire] [earch]
std::cout << '\n';
// moving container:
std::cout << "Moving container...\n";
foo = std::move(bar);
std::cout << "foo contains " << foo.size() << " elements:"; // 4
for (std::string& x : foo) std::cout << " [" << x << "]"; // [air] [water] [fire] [earch]
std::cout << '\n';
std::cout << "bar contains " << bar.size() << " elements" << std::endl; // 0
//std::cout << "bar is in an unspecified but valid state";
//std::cout << '\n';
}
{
std::string elems[10] = { "air", "water", "fire", "earth" };
// insert new element at the beginning:
std::move_backward(elems, elems + 4, elems + 5);
elems[0] = "ether";
std::cout << "elems contains:";
for (int i = 0; i<10; ++i)
std::cout << " [" << elems[i] << "]"; // [ether] [air] [water] [fire] [earch]
std::cout << '\n';
}
return 0;
}
//////////////////////////////////////////////
// random generator function:
int myrandom(int i) { return std::rand() % i; }
int test_algorithm_shuffle()
{
{
std::srand(unsigned(std::time(0)));
std::vector myvector;
// set some values:
for (int i = 1; i<10; ++i) myvector.push_back(i); // 1 2 3 4 5 6 7 8 9
// using built-in random generator:
std::random_shuffle(myvector.begin(), myvector.end());
// using myrandom:
std::random_shuffle(myvector.begin(), myvector.end(), myrandom);
// print out content:
std::cout << "myvector contains:";
for (std::vector::iterator it = myvector.begin(); it != myvector.end(); ++it)
std::cout << ' ' << *it;
std::cout << '\n';
}
{
std::array foo{ 1, 2, 3, 4, 5 };
// obtain a time-based seed:
unsigned seed = std::chrono::system_clock::now().time_since_epoch().count();
shuffle(foo.begin(), foo.end(), std::default_random_engine(seed));
std::cout << "shuffled elements:";
for (int& x : foo) std::cout << ' ' << x;
std::cout << '\n';
}
return 0;
}
//////////////////////////////////////////
int test_algorithm_remove()
{
{
int myints[] = { 10, 20, 30, 30, 20, 10, 10, 20 }; // 10 20 30 30 20 10 10 20
// bounds of range:
int* pbegin = myints; // ^
int* pend = myints + sizeof(myints) / sizeof(int); // ^ ^
pend = std::remove(pbegin, pend, 20); // 10 30 30 10 10 ? ? ?
// ^ ^
std::cout << "range contains:";
for (int* p = pbegin; p != pend; ++p)
std::cout << ' ' << *p; // 10 30 30 10 10
std::cout << '\n';
}
{
int myints[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9 }; // 1 2 3 4 5 6 7 8 9
// bounds of range:
int* pbegin = myints; // ^
int* pend = myints + sizeof(myints) / sizeof(int); // ^ ^
pend = std::remove_if(pbegin, pend, IsOdd); // 2 4 6 8 ? ? ? ? ?
// ^ ^
std::cout << "the range contains:";
for (int* p = pbegin; p != pend; ++p)
std::cout << ' ' << *p; // 2 4 6 8
std::cout << '\n';
}
{
int myints[] = { 10, 20, 30, 30, 20, 10, 10, 20 }; // 10 20 30 30 20 10 10 20
std::vector myvector(8);
std::remove_copy(myints, myints + 8, myvector.begin(), 20); // 10 30 30 10 10 0 0 0
std::cout << "myvector contains:";
for (std::vector::iterator it = myvector.begin(); it != myvector.end(); ++it)
std::cout << ' ' << *it; // 10 30 30 10 10 0 0 0
std::cout << '\n';
}
{
int myints[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
std::vector myvector(9);
std::remove_copy_if(myints, myints + 9, myvector.begin(), IsOdd);
std::cout << "myvector contains:";
for (std::vector::iterator it = myvector.begin(); it != myvector.end(); ++it)
std::cout << ' ' << *it; // 2 4 6 8 0 0 0 0 0
std::cout << '\n';
}
return 0;
}
//////////////////////////////////////////////
int test_algorithm_replace()
{
{
int myints[] = { 10, 20, 30, 30, 20, 10, 10, 20 };
std::vector myvector(myints, myints + 8); // 10 20 30 30 20 10 10 20
std::replace(myvector.begin(), myvector.end(), 20, 99); // 10 99 30 30 99 10 10 99
std::cout << "myvector contains:";
for (std::vector::iterator it = myvector.begin(); it != myvector.end(); ++it)
std::cout << ' ' << *it; // 10 99 30 30 99 10 10 99
std::cout << '\n';
}
{
std::vector myvector;
// set some values:
for (int i = 1; i<10; i++) myvector.push_back(i); // 1 2 3 4 5 6 7 8 9
std::replace_if(myvector.begin(), myvector.end(), IsOdd, 0); // 0 2 0 4 0 6 0 8 0
std::cout << "myvector contains:";
for (std::vector::iterator it = myvector.begin(); it != myvector.end(); ++it)
std::cout << ' ' << *it; // 0 2 0 4 0 6 0 8 0
std::cout << '\n';
}
{
int myints[] = { 10, 20, 30, 30, 20, 10, 10, 20 };
std::vector myvector(8);
std::replace_copy(myints, myints + 8, myvector.begin(), 20, 99);
std::cout << "myvector contains:";
for (std::vector::iterator it = myvector.begin(); it != myvector.end(); ++it)
std::cout << ' ' << *it; // 10 99 30 30 99 10 10 99
std::cout << '\n';
}
{
std::vector foo, bar;
// set some values:
for (int i = 1; i<10; i++) foo.push_back(i); // 1 2 3 4 5 6 7 8 9
bar.resize(foo.size()); // allocate space
std::replace_copy_if(foo.begin(), foo.end(), bar.begin(), IsOdd, 0); // 0 2 0 4 0 6 0 8 0
std::cout << "bar contains:";
for (std::vector::iterator it = bar.begin(); it != bar.end(); ++it)
std::cout << ' ' << *it; // 0 2 0 4 0 6 0 8 0
std::cout << '\n';
}
return 0;
}
///////////////////////////////////////////////////
int test_algorithm_reverse()
{
{
std::vector myvector;
// set some values:
for (int i = 1; i<10; ++i) myvector.push_back(i); // 1 2 3 4 5 6 7 8 9
std::reverse(myvector.begin(), myvector.end()); // 9 8 7 6 5 4 3 2 1
// print out content:
std::cout << "myvector contains:";
for (std::vector::iterator it = myvector.begin(); it != myvector.end(); ++it)
std::cout << ' ' << *it; // 9 8 7 6 5 4 3 2 1
std::cout << '\n';
}
{
int myints[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
std::vector myvector;
myvector.resize(9); // allocate space
std::reverse_copy(myints, myints + 9, myvector.begin());
// print out content:
std::cout << "myvector contains:";
for (std::vector::iterator it = myvector.begin(); it != myvector.end(); ++it)
std::cout << ' ' << *it; // 9 8 7 6 5 4 3 2 1
std::cout << '\n';
}
return 0;
}
////////////////////////////////////////////
/*
The behavior of std::rotate template (C++98) is equivalent to:
template
void rotate (ForwardIterator first, ForwardIterator middle, ForwardIterator last)
{
ForwardIterator next = middle;
while (first!=next) {
swap (*first++,*next++);
if (next==last) next=middle;
else if (first==middle) middle=next;
}
}
*/
int test_algorithm_rotate()
{
{
std::vector myvector;
// set some values:
for (int i = 1; i<10; ++i) myvector.push_back(i); // 1 2 3 4 5 6 7 8 9
std::rotate(myvector.begin(), myvector.begin() + 3, myvector.end()); // 4 5 6 7 8 9 1 2 3
// print out content:
std::cout << "myvector contains:";
for (std::vector::iterator it = myvector.begin(); it != myvector.end(); ++it)
std::cout << ' ' << *it; // 4 5 6 7 8 9 1 2 3
std::cout << '\n';
}
{
int myints[] = { 10, 20, 30, 40, 50, 60, 70 };
std::vector myvector(7);
std::rotate_copy(myints, myints + 3, myints + 7, myvector.begin());
// print out content:
std::cout << "myvector contains:";
for (std::vector::iterator it = myvector.begin(); it != myvector.end(); ++it)
std::cout << ' ' << *it; // 40 50 60 70 10 20 30
std::cout << '\n';
}
return 0;
}
//////////////////////////////////////
/*
The behavior of std::set_difference template is equivalent to:
template
OutputIterator set_difference (InputIterator1 first1, InputIterator1 last1,
InputIterator2 first2, InputIterator2 last2, OutputIterator result)
{
while (first1!=last1 && first2!=last2) {
if (*first1<*first2) { *result = *first1; ++result; ++first1; }
else if (*first2<*first1) ++first2;
else { ++first1; ++first2; }
}
return std::copy(first1,last1,result);
}
*/
int test_algorithm_set()
{
{
int first[] = { 5, 10, 15, 20, 25 };
int second[] = { 50, 40, 30, 20, 10 };
std::vector v(10); // 0 0 0 0 0 0 0 0 0 0
std::vector::iterator it;
std::sort(first, first + 5); // 5 10 15 20 25
std::sort(second, second + 5); // 10 20 30 40 50
it = std::set_difference(first, first + 5, second, second + 5, v.begin());
// 5 15 25 0 0 0 0 0 0 0
v.resize(it - v.begin()); // 5 15 25
std::cout << "The difference has " << (v.size()) << " elements:\n"; // 3
for (it = v.begin(); it != v.end(); ++it)
std::cout << ' ' << *it; // 5 15 25
std::cout << '\n';
}
{
int first[] = { 5, 10, 15, 20, 25 };
int second[] = { 50, 40, 30, 20, 10 };
std::vector v(10); // 0 0 0 0 0 0 0 0 0 0
std::vector::iterator it;
std::sort(first, first + 5); // 5 10 15 20 25
std::sort(second, second + 5); // 10 20 30 40 50
it = std::set_intersection(first, first + 5, second, second + 5, v.begin());
// 10 20 0 0 0 0 0 0 0 0
v.resize(it - v.begin()); // 10 20
std::cout << "The intersection has " << (v.size()) << " elements:\n"; // 2
for (it = v.begin(); it != v.end(); ++it)
std::cout << ' ' << *it; // 10 20
std::cout << '\n';
}
{
int first[] = { 5, 10, 15, 20, 25 };
int second[] = { 50, 40, 30, 20, 10 };
std::vector v(10); // 0 0 0 0 0 0 0 0 0 0
std::vector::iterator it;
std::sort(first, first + 5); // 5 10 15 20 25
std::sort(second, second + 5); // 10 20 30 40 50
it = std::set_symmetric_difference(first, first + 5, second, second + 5, v.begin());
// 5 15 25 30 40 50 0 0 0 0
v.resize(it - v.begin()); // 5 15 25 30 40 50
std::cout << "The symmetric difference has " << (v.size()) << " elements:\n"; // 6
for (it = v.begin(); it != v.end(); ++it)
std::cout << ' ' << *it; // 5 15 25 30 40 50
std::cout << '\n';
}
{
int first[] = { 5, 10, 15, 20, 25 };
int second[] = { 50, 40, 30, 20, 10 };
std::vector v(10); // 0 0 0 0 0 0 0 0 0 0
std::vector::iterator it;
std::sort(first, first + 5); // 5 10 15 20 25
std::sort(second, second + 5); // 10 20 30 40 50
it = std::set_union(first, first + 5, second, second + 5, v.begin());
// 5 10 15 20 25 30 40 50 0 0
v.resize(it - v.begin()); // 5 10 15 20 25 30 40 50
std::cout << "The union has " << (v.size()) << " elements:\n"; // 8
for (it = v.begin(); it != v.end(); ++it)
std::cout << ' ' << *it; // 5 10 15 20 25 30 40 50
std::cout << '\n';
}
return 0;
}
/////////////////////////////////////
int op_increase(int i) { return ++i; }
int test_algorithm_transform()
{
std::vector foo;
std::vector bar;
// set some values:
for (int i = 1; i<6; i++)
foo.push_back(i * 10); // foo: 10 20 30 40 50
bar.resize(foo.size()); // allocate space
std::transform(foo.begin(), foo.end(), bar.begin(), op_increase);
// bar: 11 21 31 41 51
// std::plus adds together its two arguments:
std::transform(foo.begin(), foo.end(), bar.begin(), foo.begin(), std::plus());
// foo: 21 41 61 81 101
std::cout << "foo contains:";
for (std::vector::iterator it = foo.begin(); it != foo.end(); ++it)
std::cout << ' ' << *it; // 21 41 61 81 101
std::cout << '\n';
return 0;
}
/////////////////////////////////////////
int test_algorithm_unique()
{
{
int myints[] = { 10, 20, 20, 20, 30, 30, 20, 20, 10 }; // 10 20 20 20 30 30 20 20 10
std::vector myvector(myints, myints + 9);
// using default comparison:
std::vector::iterator it;
it = std::unique(myvector.begin(), myvector.end()); // 10 20 30 20 10 ? ? ? ?
// ^
myvector.resize(std::distance(myvector.begin(), it)); // 10 20 30 20 10
// using predicate comparison:
std::unique(myvector.begin(), myvector.end(), myfunction); // (no changes)
// print out content:
std::cout << "myvector contains:";
for (it = myvector.begin(); it != myvector.end(); ++it)
std::cout << ' ' << *it; // 10 20 30 20 10
std::cout << '\n';
}
{
int myints[] = { 10, 20, 20, 20, 30, 30, 20, 20, 10 };
std::vector myvector(9); // 0 0 0 0 0 0 0 0 0
// using default comparison:
std::vector::iterator it;
it = std::unique_copy(myints, myints + 9, myvector.begin()); // 10 20 30 20 10 0 0 0 0
// ^
std::sort(myvector.begin(), it); // 10 10 20 20 30 0 0 0 0
// ^
// using predicate comparison:
it = std::unique_copy(myvector.begin(), it, myvector.begin(), myfunction);
// 10 20 30 20 30 0 0 0 0
// ^
myvector.resize(std::distance(myvector.begin(), it)); // 10 20 30
// print out content:
std::cout << "myvector contains:";
for (it = myvector.begin(); it != myvector.end(); ++it)
std::cout << ' ' << *it; // 10 20 30
std::cout << '\n';
}
return 0;
}
} // namespace algorithm_
