Using multiple .cpp files in c++ program?

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I recently moved from Java for C++ but now when I am writing my application I'm not interested in writing everything of the code in the main function I want in main function to call another function but this other function is in another .cpp file.

Let me explain better if you wouldn't understand:
I have one file: main.cpp inside it I have main function.

I have the second file: second.cpp inside I have a function called second() I want to call this function called second() from my main function..

Any help?

4 Answers

You can simply place a forward declaration of your second() function in your main.cpp above main(). If your second.cpp has more than one function and you want all of it in main(), put all the forward declarations of your functions in second.cpp into a header file and #include it in main.cpp.

Like this-

Second.h:

void second();
int third();
double fourth();

main.cpp:

#include <iostream>
#include "second.h"
int main()
{
    //.....
    return 0;
}

second.cpp:

void second()
{
    //...
}

int third()
{ 
    //...
    return foo;
}

double fourth()
{ 
    //...
    return f;
}

Note that: it is not necessary to #include "second.h" in second.cpp. All your compiler need is forward declarations and your linker will do the job of searching the definitions of those declarations in the other files.

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