Cant Figure out Linking Programs

[Deadly Dark]

ok so im a begginner and im trying to figure out how to link my programs together and for one i get a (File directory cannot be found) for the #include <program1.cpp> and secondly after i figured out how to fix that i had to put the whole file location i was getting this

C:\Users\Josh\Desktop\C++\Final.cpp In function 'int main()':
10 5 C:\Users\Josh\Desktop\C++\Final.cpp [Error] redefinition of 'int main()'
5 0 C:\Users\Josh\Desktop\C++\Final.cpp In file included from C:\Users\Josh\Desktop\C++\Final.cpp
6 5 C:\Users\Josh\Desktop\C++\hello1.cpp [Error] 'int main()' previously defined here
13 9 C:\Users\Josh\Desktop\C++\Final.cpp [Error] 'hello1' was not declared in this scope

#include <iostream>
#include <program1.cpp>
#include <program2.cpp>
#include <program3.cpp>

using namespace std ;

int main()
{
Program1();
program2();
program3();

getchar () ;
return 0 ;
}

[Daleth]

For your project files, use #include "" as that will first check the same directory or pathname you specified.
Do not directly include other source files. Instead, use header files.
For example:

//program1.h
#ifndef PROGRAM1_H  //these are known as include guards
#define PROGRAM1_H //They prevent duplication of code

void Program1(); //function prototype

#endif 

//program1.cpp
#include "program1.h"

void Program1(){
//...
}

Finally, all programs may only have one main function as that is the "interface," or the first function to be executed.

[SirSmilesaLot]

each program can have only one main function, which is the entry point for execution of program, looks like you are trying to include other programs with main functions:

#include <program1.cpp>
#include <program2.cpp>
#include <program3.cpp> 

you cannot do this, if u want to invoke some methods defined in some other file, try creating hpp files, in which u can define ur functions, include those hpp files in ur program, google hpp file creation for more details.

[zsteve]

like this:

main.cpp:

#include <iostream>

using namespace std;

#include "second.h" // pp if you like

int main(void)
{
	secondfunc();
	second_value=3;
}

second.h:

/* second.h */
extern int second_value; // declare second_value as extern (actual declaration of it is in the .cpp)
int secondfunc(void);		// prototype for secondfunc 

second.cpp:

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

int second_value=0;
int secondfunc(void)
{
	cout<<"This is secondfunc()"<< endln;
}

hope that helps