简单四则运算

#include<stdio.h>
int main()
{
    double a,b,ans;
    char c;
    scanf("%lf%c%lf",&a,&c,&b);
    switch(c)
    {
        case ‘+‘: ans = a+b;break;
        case ‘-‘: ans = a-b;break;
        case ‘*‘: ans = a*b;break;
        case ‘/‘: ans = a/b;break;
    }
    printf("%.2lf+%.2lf=%.2lf\n",a,b,ans);
    return 0;
}