Question

c语言有一个warning，如何去掉，

#include<stdio.h>
#include<math.h>

float area(int a,int b)
{
return (float)a*b/2;
}

float length(int a,int b)
{
return sqrt(a*a+b*b);
}

main()
{
int m,n;

float s,l;

float (*f)(int,int);

scanf("%d%d",&m,&n);

f=area;

s=(*f)(m,n);

f=length;

l=(*f)(m,n);

printf("area=%.2f,length=%.2f\n",s,l);
}

Answer 1

什么warning main 有关吗？那修改为：
int main()
{
int m,n;

float s,l;

float (*f)(int,int);

scanf("%d%d",&m,&n);

f=area;

s=(*f)(m,n);

f=length;

l=(*f)(m,n);

printf("area=%.2f,length=%.2f\n",s,l);
return 0;
}

Answer 2

main 前面加一个void
然后就是
float length(int a,int b)
{
return (float)sqrt(a*a+b*b);
}