1ii.cpp

《C/C＋＋程序设计导论（第二版）》一书的程序源文件

// Calculate the area of a circle given a radius value
#include <iostream.h>
void main()
{	float area, radius;	
	cout << "enter a radius: ";
	cin >> radius;
	area = radius * radius * 3.14;
	cout << "the area is " << area << endl;
}