例3-9 四则运算

例3-9 四则运算

程序核心——switch循环语句

程序

#include<stdio.h>
int main()
{
	double value1,value2;
	char op;
	
	printf("Type in an expression:");
	scanf("%lf%c%lf",&value1,&op,&value2);
	switch(op)
	{
		case'+':printf("=%.2f",value1+value2);
				break;
		case'-':printf("=%.2f",value1-value2);
				break;
		case'*':printf("=%.2f",value1*value2);
				break;
		case'/':printf("=%.2f",value1/value2);
				break;
		default:printf("Unknown operator\n");
				break;
	}
	return 0;	
 } 

结果

Type in an expression:9.9+0.01
=9.91
--------------------------------
Process exited after 14.53 seconds with return value 0
请按任意键继续. . .

分析

重点：switch语句判断的是一个常量