Help Please

How would i make this create an error message if a number was divided by 0

Code:

#include <iostream>
using namespace std;

int main ()
{
	// Variable Declarations
	int num1, num2, num3, num4;
	char letter = 'y', symbol;
    
    // Prompt 
	cout << "This Program will add, subtract, multiply, and divide" 
		 << "the two numbers you enter." << endl;
    cout << endl;

	do
	{
        cout << "Please enter two numbers: ";
		cin >> num1 >> num2;
		cout << endl;

		cout << "Please input the operation you would like to use: ";
		cin >> symbol;
		cout << endl;

		switch (symbol)
		{
		case '+': num3 = num1 + num2;
			cout << "The sum is: " << num3 << endl;
		    break;
		case '-': num3 = num1 - num2;
			cout << "The difference is: " << num3 << endl;
		    break;
		case '*': num3 = num1 * num2;
			cout << "The product is: " << num3 << endl;
			break;
		case '/': num3 = num1 / num2;
			num4 = num1 % num2;
			cout << "The Quotient is: " << num3 << " The Remainder is: "<< num4 << endl;
		}
        cout << "Would you like to run the program again [y/n] ";
		cin >> letter;
		cout << endl;
	}
	while (letter == 'y');
	    cout << "End of Program" << endl;

	return 0;
}

Simply do a check if num2 is zero BEFORE you do any division on it, then print an error.