使用main函数的参数，实现一个整数计算器 C语言

#pragma warning (disable:4996)
#include<stdio.h>
#include<stdlib.h>
#include<assert.h>
int my_math(char *p, int num1, int num2)
{
assert(p);
if (p == "-a")
return num1 + num2;
else if (p == "-s")
return num1 - num2;
else if (p == "-m")
return num1*num2;
else if (p == "-d")
return num1 / num2;
else return 0;
}
int main()
{
char a, b;
char *p = &b;
int num1 = 0;
int num2 = 0;
printf("请输入要计算的算式：");
scanf("%d%c%d", &num1, &a, &num2);  //num1,num2为操作数，a保存的是操作符
while (1)      //分别对参数指针p赋值，‘+’，‘-’，‘*’，‘/’，分别对应“-a,-s,-m,-d”,如果别的符号队p赋‘\0’
{
if (a == '+')
{
p = "-a";
break;
}
else if (a == '-')
{
p = "-s";
break;
}
else if (a == '*')
{
p = "-m";
break;
}
else if (a == '/')
{
p = "-d";
break;
}
else *p = '\0';
}
int result = my_math(p, num1, num2);
printf("%d%c%d=%d\n", num1, a, num2, result);
system("pause");
return 0;
}