例3-5 四则运算

四则运算

程序核心——判断语句

程序

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

结果

Type in an expression:3*10
=30.00

--------------------------------
Process exited after 7.727 seconds with return value 0
请按任意键继续. . .
.

分析

重点：判断语句，注意判断条件,在判断字符时要加’’才可以