求助~~24速算的C语言编程~~

在VC6.0下可通过编译并运行
#include<stdio.h>
double ok(double n1,double n2,char c) /*计算两数运算结果*/
{
if(c=='+') return n1+n2;
if(c=='-') return n1-n2;
if(c=='*') return n1*n2;
if(c=='&#