lab2_3.cpp

几个c++实验程序 对初学者很有帮助的

#include <iostream.h>

const float PI = 3.1416;

void main()
{
	int iType;
	float radius, a, b, area;
	
	cout << "图形的类型为?(1-圆形 2-长方形 3-正方形):";
	cin >> iType;
	switch(iType)
	{
	case 1:
		cout << "圆的半径为：";
		cin >> radius;
		area = PI * radius * radius;
		cout<<"面积为："<<area<<endl;
		break;
	case 2:
		cout << "矩形的长为：";
		cin >> a;
		cout << "矩形的宽为：";
		cin >> b;
		area = a * b;
	    cout<<"面积为："<<area<<endl;
		break;
	case 3:
		cout << "正方形的边长为：";
		cin >> a;
		area = a * a;
    	cout<<"面积为："<<area<<endl;
		break;
	default:
		cout << "不是合法的输入值!"<<endl;
	}
}