How do I call different variables from one function to another?

[Daniel Steel]

So, here's the issue.
I was told to make a basic calculator with Addition, Subtraction, Multiplication and Division functions. The program will first take the input of two numbers and a character, all in another function. The character will be used to determine which operation is to be used. Sort of like this:

#include <iostream>
using namespace std;

int Calculator();

int main()
{
	int S;

	S = Calculator();

	if (S == '+')
	{
		Addition();
	}
	else if (S == '-')
	{
		Subtraction();
	}
	else if (S == 'x')
	{
		Multiplication();
	}
	else if (S == '/')
	{
		Division();
	}

	
}

int Calculator()
{
	int Num1 = {}, Num2 = {};
	char Operation;

	cout << "Welcome!" << endl;
	cout << "Please enter First Number here: ";
	cin >> Num1;
	cout << "Please Enter Second Number here: ";
	cin >> Num2;
	cout << endl;
	cout << "Please select the operation from the following: " << endl;
	cout << "(Addition = +; Subtraction = -; Multiplication = x; Division = /)" << endl;
	cout << "Enter here: ";
	cin >> Operation;

	while (Operation != '+' && Operation != '-' && Operation != 'x' && Operation != '/')
	{
		cout << "Invalid Input. Please try again." << endl;
		cout << "Enter here: ";
		cin >> Operation;
	}

	return Operation;
}

(I know this doesn't work, this is the most I could get right)

Here's the problem, though. How do I get the two input values into the the other functions? The values are supposed to be taken in the Calculator function only.

[Peter87]

Doesn't it make more sense to call Addition, Subtraction, Multiplication and Division from within Calculator? Then you could pass the values of Num1 and Num2 as arguments to these functions.

[seeplus]

Based upon the OP design, then possibly something like this:

#include <iostream>

int Calculator(int&, int&);
int Addition(int, int);
int Subtraction(int, int);
int Multiplication(int, int);
int Division(int, int);

int main() {
	int v1 {}, v2 {}, result {};

	int S {Calculator(v1, v2)};

	if (S == '+')
		result = Addition(v1, v2);
	else if (S == '-')
		result = Subtraction(v1, v2);
	else if (S == 'x')
		result = Multiplication(v1, v2);
	else
		result = Division(v1, v2);

	std::cout << "Result is " << result << '\n';
}

int Addition(int n1, int n2) { return n1 + n2; }
int Subtraction(int n1, int n2) { return n1 - n2; }
int Multiplication(int n1, int n2) { return n1 * n2; }
int Division(int n1, int n2) { return n1 / n2; }

int Calculator(int& Num1, int& Num2) {
	char Operation {};

	std::cout << "Welcome!\n";
	std::cout << "Please enter First Number here: ";
	std::cin >> Num1;

	std::cout << "Please Enter Second Number here: ";
	std::cin >> Num2;

	std::cout << "\nPlease select the operation from the following:\n";
	std::cout << "(Addition = +; Subtraction = -; Multiplication = x; Division = /)\n";

	do {
		std::cout << "Enter here: ";
		std::cin >> Operation;

	} while (Operation != '+' && Operation != '-' && Operation != 'x' && Operation != '/' &&
		(std::cout << "Invalid Input. Please try again.\n"));

	return Operation;
}

Note that * is usually used for multiplication rather than x. Also note that division is integer - so 7 / 4 is 1.