use a variable defined in main from another source file?

[mindheavy]

is it possible if I define a variable, say... int oranges = 0; in main.cpp and alter it like:

cout << "How many? << endl;
cin >> oranges; 

and have another .cpp file that has a function
eatOranges() use that variable oranges even though it's being defined and messed with in main.cpp?

[shacktar]

Yes, here is an example (with parameter passing):

//Oranges.h
#ifndef _Oranges_Included_
#define _Oranges_Included_

void eatOranges(int numOranges);

#endif 

//Oranges.cpp
#include "Oranges.h"

#include <iostream>

void eatOranges(int numOranges)
{
   std::cout << "Eating " << numOranges << " oranges" << std::endl;
}

//Main.cpp
#include "Oranges.h"

#include <iostream>
#include <limits>

int main()
{
   int oranges = 0;

   std::cout << "How many?" << std::endl;
   std::cin >> oranges;

   eatOranges(oranges);

   std::cout << "Press enter to continue..."<< std::endl;
   std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
   
   return 0;
}

[vlad from moscow]

You should either to pass this variable as an argument to the function or declare it with external linkage.