206.cpp

来自「C++实训教程」· C++ 代码 · 共 22 行

/*
	206.cpp
	Written By S.Y.Feng
	DEMO 演示 注释和const的使用
*/
#include <iostream.h>
const float PI = 3.1415926; //用const来固定PI变量—— 
float Area(float r);  //函数的原型
main()
{
   float radius;	//圆的半径
   cout << "Enter the radius of a circle: ";
   cin >> radius;
   cout << "The Area is " << Area(radius) << "\n";
}
float Area(float r) //函数定义的头部
{return PI * r * r;}
/*
Enter the radius of a circle: 10
The Area is 314.159

*/