程序出现undefined reference to fax(int.int.int)'该怎么解决

Question

#include

using namespace std;

int main()
{
int x,y,m;
cin>>x>>y;
void fax(int,int,int);
int sum(int,int);
int max1(int,int);
fax(sum(x,y),x,y);
fax(max1(x,y),x,y);
return 0;
}
void fax(int (*p)(int,int),int a,int b)
{
int result;
result=(*p)(a,b);
//return result;
cout<<result<<endl;
}
int sum(int a,int b)
{
return a+b;
}
int max1(int a,int b)
{
return a>b?a:b;
}

Answer 1

把

void fax(int (*p)(int,int),int a,int b);
int sum(int a,int b);
int max1(int a,int b);

添加到int main前面

#include<bits/stdc++.h>

using namespace std;
void fax(int (*p)(int,int),int a,int b);
int sum(int a,int b);
int max1(int a,int b);
int main()
{
int x,y,m;
cin>>x>>y;
void fax(int,int,int);
int sum(int,int);
int max1(int,int);
fax(sum(x,y),x,y);
fax(max1(x,y),x,y);
return 0;
}
void fax(int (*p)(int,int),int a,int b)
{
int result;
result=(*p)(a,b);
//return result;
cout<<result<<endl;
}
int sum(int a,int b)
{
return a+b;
}
int max1(int a,int b)
{
return a>b?a:b;
}