C语言简单问题，看看哪里出错

Question

#include
int main()
{
int a, b, c;

if (a + b)

{
c = add main(a,b);
printf("c = %d\n",add main(a, b));
}

else

{ c = sub main(a,b);
printf("c = %d\n",sub main(a, b));
}
}

add main(int a, int b)
{
return a + b;
}

sub main(int a, int b)
{
return a - b;
}

Answer 1

没有add和sub类型，而且main不要用来做函数名，函数没有先声明应该都放main函数前面，还有就是include后面最好写清楚头文件名。代码给你改好放在这里了：

 #include<stdio.h>

int add(int a, int b)
{
return a + b;
}

int sub(int a, int b)
{
return a - b;
}

int main()
{
int a, b, c;
if (a + b)
{
c = add(a,b);
printf("c = %d\n",add(a, b));
}
else
{ c = sub(a,b);
printf("c = %d\n",sub(a, b));
}
}