How to use a variable from other functions - c++

Question

int calculateX()
{
int x;
cout<<"Enter value for x: ";
cin>>x;
return x;
}
int anotherFunction()
{
/////
}
int main()
{
calculateX();
anotherFunction();
return 0;
}
This is an example on a code. How do can I possibly use the input from the user in the calculateX() function into the function anotherFunction() ?

Answer 1

You have to use function parameters:
int calculateX()
{
int x;
cout<<"Enter value for x: ";
cin>>x;
return x;
}
int anotherFunction(int x)
{
/////
}
int main()
{
int x = calculateX();
anotherFunction(x);
return 0;
}

Answer 2

what you need is either a pass by value , which is already answered or a global variable like this
#include <iostream>
using namespace std;
// Global variable declaration:
int g;
int anotherFunction()
{
cout << g;
}
int main () {
// Local variable declaration:
int a, b;
a = 10;
b = 20;
g = a + b;
anotherFunction();
return 0;
}
A global variable can be accessed by any function. That is, a global variable is available for use throughout your entire program after its declaration.

Answer 3

You must declare the variable x global (outside the calculateX() function), so that anotherFunction() can see it. If you define the variable x inside the calculateX() function, it will be deleted after exiting the function.
int x;
int calculateX()
{
cout<<"Enter value for x: ";
cin >> x;
return x;
}
int anotherFunction()
{
/////
}
int main()
{
calculateX();
anotherFunction();
return 0;
}

Answer 4

Function generally has return type before it's name. For Example :
int calculateX() {
int x;
cout<<"Enter value for x: ";
cin>>x;
anotherFunction(x)
return x;
}
int is here return type.And you are calling two functions from your main function. calculateX has a variable of type int named x. So, you can't access x from outside of calculateX scope. But you can return it to your main function and store it in a different variable so that It becomes available in main function. Once It becomes available, you can send it as argument to another function . In your case It should be like this :
int anotherFunction(int valueFromMain)
{
std::cout << valueFromMain << std::endl;
}
int main(){
int returnedFromCalculateX = calculateX(); //You have returned value available on main Function
anotherFunction(returnedFromCalculateX); //Send It to anotherFunction(pass by value)
return 0;
}
You can also send the value as a reference. That needs a bit higher understanding. Please Check : https://www.w3schools.com/cpp/cpp_function_reference.asp for more details.