第七章 STL 及其应用

#include
#include
#include
using namespace std;

class Predicate{
private:
  int count=0;
public:
  bool operator()(int data){
    if ( count>=3 ) return false;
    else{
      bool x=(data<=20 && data%3==0);
      count+=x;
     // cout< vec{2,4,5,6,10,15,3,21,36,72,9,13};
 vector result;
 result.resize (vec.size());
// auto end=copy_if(vec.begin (),vec.end (),result.begin(),predicate);
 int count=0;
 auto end=copy_if(vec.begin (),vec.end (),result.begin()
                  ,[&count](int data)->bool{    
                      if ( count>=3 ) return false;
                      else{
                        bool x=(data<=20 && data%3==0);
                        count+=x;return x;
                      }
                    }
                  );

 result.erase(end,result.end ());
 for_each(result.begin (),result.end (),[](int e){cout<

6
15
3
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#include 
#include 
#include 

Test2:
Welcome to the Student Management System!
But can I must say the our teacher has less creativity in teaching...
In two continuous semeters this project always is the hardest task...
I only look foward there will be some intersting task in the 14-15th week.

#include
using namespace std;



int main(){
  map count;//save as pair
  string word;
  int n;cin>>n;
  while(n--) {
    cin>>word;
    ++count[word];
  }
  for(auto e:count){//what inside map ??????
    cout<

看情况

#include
#include 

#include
#include 

#include
#include
#include

using namespace std;

using namespace std::placeholders;

int main(){
  auto divd=[](auto x,auto y){return x/y;};
  auto dint=bind(divd,_1,_2);
  auto rddou=bind(divd,_2,_1);
  cout<

include

using namespace std;

int main(){
enum week{Monday,Tuesday,Wednesday};

week a=Monday;
a=(week)1;
cout<<&a< cout<<(int)a< cout< }

0x7ffee452bb3c
1
1
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#include
#include
#include
#include
#include
using namespace std;
void myfunction (int i)
{
    cout << " " << i;
}
struct myclass
{
    void operator() (int i)
    {
        cout << " " << i;
    }
} myobject;

class MeanVlaue
{
public:
    MeanVlaue():num(0),sum(0){}
    void operator() (int elem)
    {
        num++;
        sum+=elem;
    }
    double value()
    {
        return static_cast(sum)/static_cast(num);
    }
    operator double()//重载的好处，简洁！
    {
        return static_cast(sum)/static_cast(num);
    }
private:
    long num;
    long sum;
};

template
auto add(T1 &a)->decltype(a+10){
  return a+=10;
}

template
class AddValue
{
public:
    AddValue(const T& v):theValue(v){}
    void operator() (T& elem)const
    {
        elem+=theValue;
    }
private:
    T theValue;
};

int main()
{
    vector myvector;
    myvector.push_back(10);
    myvector.push_back(20);
    myvector.push_back(30);

    cout << "myvector contains:";
    for_each (myvector.begin(), myvector.end(), myfunction);

    // or:
    cout << "\nmyvector contains:";
    for_each (myvector.begin(), myvector.end(), myobject);

    cout << endl;

    MeanVlaue mv=for_each(myvector.begin(),myvector.end(),MeanVlaue());
    cout<<"MeanValue:"<);//参数可以自己改，eg：*(myvector.begin())
    for_each (myvector.begin(), myvector.end(), myobject);
    cout << endl;

    double mv2=for_each(myvector.begin(),myvector.end(),MeanVlaue());
    cout<<"MeanValue:"<

myvector contains: 10 20 30
myvector contains: 10 20 30
MeanValue:20
20 30 40
MeanValue:30
[Finished in 0.4s]

```java
#include
#include
using namespace std;

template
T use_f(T x,function f){
  static int count=0;
  ++count;
  cout<<"count = "<#include
#include
#include
using namespace std;

#define all(x) x.begin(),x.end()

int main(){
  vector vec1(10,10),vec2(10,11);
  for_each(all(vec1),[](int x){cout<

10 10 10 10 10 10 10 10 10 10 
0
1
100 100 100 100 100 100 100 100 100 100 
2
3
1100 1100 1100 1100 1100 1100 1100 1100 1100 1100 
4
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#include
using namespace std;
#define all(x) x.begin(),x.end()
#define pb push_back

template
void out(T x){
  cout< vec;
  cout<);
  cout< vec2(vec);
  reverse(all(vec));
  for_each(all(vec),out);
  cout<);
  cout<);
  cout<

#include 
#include  
using namespace std;
#define all(x) x.begin(),x.end()
#define pb push_back

template
void out(T x){
  cout< vec;
  cout<);
  cout< vec2(vec);
  reverse(all(vec));
  for_each(all(vec),out);
  cout<);
  cout<);
  cout<