为什么我的程序仅适用于调试版本？

Question

I have a project that has the main method accessing another method from another source file, BigDog(int) . I'm pretty sure the code is right but CodeBlocks seems to not be able to detect the definition of the method unless I build the other file using debug build in CodeBlocks. In Release, I get the following error when building:

Error: undefined reference to 'BigDog(int)'

Why is that so?

main.cpp

#include <iostream>

using namespace std;

void BigDog(int KibblesCount);

int main()
{
   BigDog(3);
   return 0;
}

mystuff.cpp

 #include <iostream>

 using namespace std;

 void BigDog(int KibblesCount)
 {
     cout << KibblesCount;
 }

Answer 1

If you're adding a new file in codeblocks, make sure to check the checkmarks in the dialog to add it to both the debug and the release build.

Also its better practice to move your declarations to a header file and include that where needed, like this:

main.cpp:

#include "mystuff.h"

int main()
{
    BigDog(3);
    return 0;
}

mystuff.h:

#pragma once

void BigDog(int KibblesCount);

mystuff.cpp:

#include "mystuff.h"

#include <iostream>

void BigDog(int KibblesCount)
{
    // add a newline so the line gets printed immediately
    std::cout << KibblesCount << "\n"; 
}