C ++ Code :: Blocks不使用头文件进行编译

Question

Good evening! (morning?)

I was wondering if anyone is familiar with the following issues. There are three files here, which are Cat.cpp, Cat.h, and CatMain.cpp. The issues are as follows:

When I try to build Cat.cpp, I get the error "undefined reference to WinMain@16".

When I try to build CatMain.cpp, I get undefined reference errors for the speak and jump functions.

The files are in the same folder and the code is just one-liners:

Cat.cpp

#include <iostream>
#include "Cat.h"

using namespace std;

void speak()
{
    cout << "meow" << endl;
}

void jump()
{
    cout << "meow?" << endl;
}

Cat.h

#ifndef CAT_H
#define CAT_H

void speak();
void jump();

#endif // CAT_H

CatMain.cpp

#include <iostream>
#include "Cat.h"

using namespace std;

int main()
{
    speak();
    jump();
    return 0;
}

Is there anything wrong with this code? Or is anyone aware of whether or not this is a Code::Blocks or a compiler issue?

Any help is greatly appreciated =)

Answer 1

All that your code does as of now is something like this :

Cat.cpp ::

#include <iostream>
using namespace std;
void speak();
void jump();
void speak()
{
    cout << "meow" << endl;
}

void jump()
{
    cout << "meow?" << endl;
}

CatMain.cpp ::

#include <iostream>

using namespace std;
void speak();
void jump();
int main()
{
    speak();
    jump();
    return 0;
}

You Cat.cpp has a main method missing because of which it wouldn't compile.

Your CatMain.cpp does not have any definition for speak() and jump() , hence undefined error.

Point : CatMain.cpp doesn't know what Cat.cpp is trying to work out.

int main() { return 0; }

added to Cat.cpp should let it compile.

void speak(){
    cout << "defined" << endl;
}

void jump(){
    cout << "defined" << endl;
}

added to CatMain.app should work for it as well.

Answer 2

Your code is fine. Most probably you don't want to compile separate files but project as whole. You should add both cpp to project in your IDE and linker will link them together resolving both issues.