include's

[rdnjr]

(Can/How do) you include a header file into two different functions that will be compiled into the same program?! ex...


// main.c

#include <iostream>

#include "cat.h"

using namespace std;

int main()
{
cat spot;
spot.age = 2;
printage(spot);
return 0;
}


//printage.c

#include cat.h"
#include <iostream>

using namespace std;

void printage(cat fluffy)
{
cout << fluffy.age << '\n';
return;
}


//cat.h

class cat
{
int age;
};

cat::cat()
{
age = 0;
}


When this is compiled, it throws out the errors:

/tmp/ccN6V3Pd.o: In function 'cat::cat[not-in-charge]()':
/tmp/ccN6V3Pd.o(.text+0x0): multiple definition of 'cat::cat[not-in-charge]()'
/tmp/ccQuUmOM.o: (.text+0x0): first defined here
/tmp/ccN6V3Pd.o: In function 'cat::cat[in-charge]()':
/tmp/ccM6V3Pd.o(.text+0x68): multiple definition of cat::cat[in-charge]()'
/tmp/ccQuUmOM.o(.text+0x68): first defined here
collect2: ld returned 1 exit status


The command I use to compile is: g++ main.c printage.c -o main
I'm using RedHat 8.0 with gcc3.2.

[SilentStrike]

You need to use include guards so that the code isn't included twice.

For example, cat.h should look like this...

#ifndef CAT_H
#define CAT_H

// rest of cat.h

#endif

While that will allow you to have multiple include files, you should really learn about the linking process, which is even more complicated . This way, you can have multiple SOURCE files.

[rdnjr]

Thanks, that worked. Do you know where I can get the information you mentioned about the linking process?