//c++语言程序设计第二章习题
//2-4
#include <iostream>
using namespace std;
int main()
{
const double PI = 3.1416;
double a;
a = PI;
cout<<"a的值为："<<a<<endl;
return 0;
}
1 //c++语言程序设计第二章习题
2 //2-11
3 #include <iostream>
4 using namespace std;
5 int main()
6 {
7 int n =100;
8 for(int n=100;n<=200;n+=2){}
9 do{int n=100;n+=2;}while(n!=200);
10 while(n!=200){n+=2;}
11 return 0;
12 }
1 //c++语言程序设计第二章习题
2 //2-13
3 #include <iostream>
4 using namespace std;
5 int main()
6 {
7 int x;
8 int y;
9 cout<<"请输入x,y的值"<<endl;
10 cin>>x>>y;
11 int temp;
12 if(x>y||x<y)
13 {
14 temp = y;
15 y = x;
16 x = temp;
17 }
18 cout<<"x = "<<x<<endl;
19 cout<<"y = "<<y<<endl;
20 return 0;
21 }
1 //c++语言程序设计第二章习题
2 //2-16
3 #include <iostream>
4 using namespace std;
5 int main()
6 {
7 cout<<"int字节数为："<<sizeof(int)<<endl;
8 cout<<"char字节数为："<<sizeof(char)<<endl;
9 cout<<"float字节数为："<<sizeof(float)<<endl;
10 cout<<"double字节数为："<<sizeof(double)<<endl;
11 return 0;
12 }
1 //c++语言程序设计第二章习题
2 //2-17
3 #include <iostream>
4 using namespace std;
5 int main()
6 {
7 int num = 0;
8 for(int i=32;i<=127;i++)
9 {
10 cout<<(char)i<<"\t";
11 num++;
12 if(num == 4)
13 {
14 num = 0;
15 cout<<endl;
16 }
17 }
18 return 0;
19 }
