9-1-2.cpp

学习c++的ppt

#include <iostream.h>
const double PI=3.1415;
double length(float r)
{    return 2*PI*r;
}
double length(float x,float y)
{    return 2*(x+y);
}
void main()
{   float a,b,r;
     cout << "输入圆半径：";
     cin >>  r;
     cout << "圆周长：" <<length(r) <<endl;
     cout << "输入矩形长和宽：";
     cin >> a >> b;
     cout << "矩形周长："
             << length(a, b) <<endl;
}