How to create a global variable?

[Mister Richards]

I am trying to create a global variable in C++. I am fairly new to C++ and keep getting an error message my getDoubleNumbr function does not recognize the number variable. I know that the error is because the number vaiable is local to the main function. To fix this error i am trying to create a global variable.

#include <iostream>
using namespace std;
 
//declare global variable
int numbeer = 0;
 
//function prototype
int getDoubleNumber();
 
int main()
{
    //declare variables
    int number       = 0;
    int doubleNumber = 0;
 
    //get input item
    cout << "Enter a number: ";
    cin >> number;
 
    //double the number
    doubleNumber = getDoubleNumber();
 
    //display result
    cout << "Answer: " << doubleNumber << endl;
 
    system("pause");
    return 0;
}    //end of main function
 
//*****function definitions*****
int getDoubleNumber()
{
    return number * 2;
}    //end of getDoubleNumber functi

on

[whodgson]

Your global variable is 'numbeer'.
Your local to main() variable is 'number'.

[Mister Richards]

so how do i make the fix so that number is the global variable and not the local variable? i want the program to run without giving me the error message.

[whodgson]

change the word number to numbeer in lines 18 and 32

[horace1]

in C++ you can have a global variable and a local variable using the same identifier and use the scope resolution operator :: to access the global variable, e.g.

//declare global variable
int number = 10;
 
int main()
{
    //declare variables
    int number       = 20;
    cout << "local number " << number << " global number " << ::number << endl;
 }
 

when run gives

local number 20 global number 10

no recommended as it can lead to confusing and difficult to debug code, i.e. you forget the ::