记录我看C++ Primer Plus(第六版)第九章源代码
后面有几个程序是讲命名空间的,我只是了解了一下并没有学习书上代码
9.1
#ifndef COORDIN_H_
#define COORDIN_H_
struct polar
{
double distance;
double angle;
};
struct rect
{
double x;
double y;
};
polar rect_to_polar(rect xypos);
void show_polar(polar dapos);
#endif
9.2
#includes
#include"coordin.h"
#include"9.3.cpp"
using namespace std;
int main()
{
rect rplace;
polar pplace;
cout <<"Enter the x and y values: ";
while(cin>>rplace.x>>rplace.y)
{
pplace = rect_to_polar(rplace);
show_polar(pplace);
cout << "Next two numbers (q to quit): ";
}
cout << "Bye!\n";
return 0;
}
9.3
#include
#include
#include"coordin.h"
polar rect_to_polar(rect xypos)
{
using namespace std;
polar answer;
answer.distance = sqrt(xypos.x * xypos.x + xypos.y * xypos.y);
answer.angle = atan2(xypos.y, xypos.x);
return answer;
}
void show_polar(polar dapos)
{
using namespace std;
const double Rad_to_deg = 57.29577951;
cout << "distance = " << dapos.distance;
cout << ",angle = " << dapos.angle * Rad_to_deg;
cout << " degrees\n";
}
9.4
#include
void oil(int x);
int main()
{
using namespace std;
int texas = 31;
int year = 2013;
cout << " In main (),texas = " << texas << ",&texas = ";
cout << &texas << endl;
cout << " In main(),year = " << year << ", &year = ";
cout << &year << endl;
oil(texas);
cout << "In main(),texas = " << texas << ", & texas = ";
cout << &texas << endl;
cout << " In main(),year = " << year << ", &year = ";
cout << &year << endl;
return 0;
}
void oil(int x)
{
using namespace std;
int texas = 5;
cout << "In oil(),texas = " << texas << ",&texas = ";
cout << &texas << endl;
cout << "In oil(),x = " << x << ", &x = ";
cout << &x << endl;
{
int texas = 133;
cout << "In block, texas = " << texas;
cout << ",&texas = " << &texas << endl;
cout << "In block,x = " << x << ", &x = ";
cout << &x << endl;
}
cout << "Post-block texas = " << texas;
cout << ",&texas = " << &texas << endl;
}
9.5
#include
#include"9.6.cpp"
using namespace std;
double warming = 0.3;
void update(double dt);
void local();
int main()
{
cout << "Global warming is " << warming << " degrees.\n";
update(0.1);
cout << "Global warming is " << warming << " degrees.\n";
local();
cout << "Global warming is " << warming << " degrees.\n";
return 0;
}
9.6
#include
extern double warming;
void update(double dt);
void local();
using std::cout;
void update(double dt)
{
extern double warming;
warming += dt;
cout << "Updating global warming to " << warming;
cout << " degrees.\n";
}
void local()
{
double warming = 0.8;
cout << "Local warming = " << warming << " degrees.\n";
cout << "But global warming = " << ::warming;
cout << " degrees.\n";
}
9.7
#include
int tom = 3;
int dick = 30;
static int harry = 300;
void remote_access();
int main()
{
using namespace std;
cout << "main() reports the following addresses:\n";
cout << &tom << " = &tom," << &dick << " = &dick, ";
cout << &harry << " = &harry\n";
remote_access();
return 0;
}
9.8
#include
extern int tom;
static int dick = 10;
int harry = 200;
void remote_access()
{
using namespace std;
cout << "remoto_access() reports the following addresses:\n";
cout << &tom << " = &tom, " << &dick << " = &dick, ";
cout << &harry << " = &harry\n";
}
9.9
#include
const int ArSize = 10;
void strcount(const char *str);
int main()
{
using namespace std;
char input[ArSize];
char next;
cout << "Enter a line:\n";
cin.get(input, ArSize);
while(cin)
{
cin.get(next);//清空缓冲区小操作
while(next!='\n')
cin.get(next);
strcount(input);
cout << "Enter next line (empty line to quit):\n";
cin.get(input, ArSize);
}
cout << "Bye\n";
return 0;
}
void strcount(const char *str)
{
using namespace std;
static int total = 0;
int count = 0;
cout << "\"" << str << "\"contains ";
while (*str++)
count++;
total += count;
cout << count << " characters\n";
cout << total << " characters total\n";
}
9.10
#include
#include
const int BUF = 512;
const int N = 5;
char buffer[BUF];
int main()
{
using namespace std;
double *pd1, *pd2;
int i;
cout << "Calling new and placement new :\n";
pd1 = new double[N];
pd2 = new (buffer) double[N];
for (i = 0; i < N;i++)
pd2[i] = pd1[i] = 100 + 20.0 * i;
cout << "Memory addresse:\n"
<< " heap: " << pd1
<< " static: " << (void *)buffer << endl;
cout << "Memory contents:\n";
for (i = 0; i < N;i++)
{
cout << pd1[i] << " at " << &pd1[i] << "; ";
cout << pd2[i] << " at " << &pd2[i] << endl;
}
cout << "\nCalling new and placement new a second time:\n";
double *pd3, *pd4;
pd3 = new double[N];
pd4 = new (buffer) double[N];
for (i = 0; i < N;i++)
pd4[i] = pd3[i] = 1000 + 40.0 * i;
cout << "Meory contents:\n";
for (i = 0; i < N;i++)
{
cout << pd3[i] << " at " << &pd3[i] << "; ";
cout << pd4[i] << " at " << &pd4[i] << endl;
}
cout << "\nCalling new and placement new a third time:\n";
delete[] pd1;
pd1 = new double[N];
pd2 = new (buffer + N * sizeof(double)) double[N];
for (i = 0; i < N;i++)
pd2[i] = pd1[i] = 1000 + 60.0 * i;
cout << "Memory contents:\n";
for (i = 0; i < N;i++)
{
cout << pd1[i] << " at " << &pd1[i] << "; ";
cout << pd2[i] << " at " << &pd2[i] << endl;
}
delete[] pd1;
delete[] pd3;
return 0;
}