How to loop back to main menu?

[9ypNhbRD]

Okay I made this program which basically has a menu and will have different options given at the menu. The user can choose to run different parts of the program for example the calculator. What I would like is for the user to be able to run different parts of the program and then go back to the menu. Also, as soon as you do something in the calculator or any other parts of the program the program closes. How do i keep it running?

#include"stdafx.h" 
#include<iostream>
#include<math.h>
using namespace std;

int calculator()
{
	int number1, number2, result, z;
	double PI = 3.1416;

	cout << " _____________________________________________________ " << endl;
	cout << "|                      Calculator                     |" << endl;
	cout << "|_____________________________________________________|" << endl;
	cout << "|  ____   ____   ____   |  ____   ____   ____   ____  |" << endl;
	cout << "| |sin7| |cos8| |tan9|  | |  1 | | 2  | |  3 | |+(1)| |" << endl;
	cout << "| |____| |____| |____|  | |___ | |____| |____| |____| |" << endl;
	cout << "|  _____  _____  ____   |  ____   ____   ____   ____  |" << endl;
	cout << "| |e^x11||sqr10||Ln 6|  | |  4 | | 5  | |  6 | |-(2)| |" << endl;
	cout << "| |_____||_____||____|  | |___ | |____| |____| |____| |" << endl;
	cout << "|  ____                 |  ____   ____   ____   ____  |" << endl;
	cout << "| |Log5|                | |  7 | | 8  | |  9 | |*(3)| |" << endl;
	cout << "| |____|                | |____| |____| |____| |____| |" << endl;
	cout << "|                       |         ____          ____  |" << endl;
	cout << "|                       |        | 0  |        |/(4)| |" << endl;
	cout << "|                       |        |____|        |____| |" << endl;
	cout << "|_____________________________________________________|" << endl;
	cout << "" << endl;
	cout << "" << endl;
	cout << "Please Pick the number of the operation you wish to use" << endl;
	cin >> z;
	cout << "" << endl;
	cout << "" << endl;

	switch (z)
	{
	case 1:
		cout << "Type in first number.\n" << endl;
		cin >> number1;
		cout << "Type in second number.\n" << endl;
		cin >> number2;
		result = number1 + number2;
		cout << "" << endl;
		cout << result << endl;
		system("pause");
		return 0;



	case 2:
		cout << "Type in first number.\n" << endl;
		cin >> number1;
		cout << "Type in second number.\n" << endl;
		cout << "" << endl;
		cin >> number2;
		result = number1 - number2;
		cout << "" << endl;
		cout << result << endl;
		system("pause");
		return 0;

	case 3:
		cout << "Type in first number.\n" << endl;
		cin >> number1;
		cout << "Type in second number.\n" << endl;
		cin >> number2;
		result = number1 * number2;
		cout << "" << endl;
		cout << result << endl;
		system("pause");
		return 0;

	case 4:
		cout << "Type in first number.\n" << endl;
		cin >> number1;
		cout << "Type in second number.\n" << endl;
		cin >> number2;
		result = number1 / number2;
		cout << "" << endl;
		cout << result << endl;
		system("pause");
		return 0;

	case 5:
		cout << "Type in number.\n" << endl;
		cin >> number1;
		double param, result;
		param = number1;
		result = log10(param);
		cout << "" << endl;
		printf("log(%f) = %f\n", param, result);
		system("pause");
		return 0;

	case 6:
		cout << "Type in number.\n" << endl;
		cin >> number1;
		result = log(number1);
		cout << "" << endl;
		cout << "Ln(number)=" << result << endl;
		system("pause");
		return 0;


	case 7:
		cout << "Type in Angle.\n" << endl;
		cin >> number1;
		result = sin(number1*PI / 180);
		cout << "" << endl;
		cout << result << endl;
		system("pause");
		return 0;

	case 8:
		cout << "Type in a angle in degrees.\n" << endl;
		cin >> number1;
		result = cos(number1*PI / 180);
		cout << "" << endl;
		cout << result << endl;
		system("pause");
		return 0;

	case 9:
		cout << "Type in a angle in degrees.\n" << endl;
		cin >> number1;
		result = tan(number1*PI / 180);
		cout << "" << endl;
		cout << result << endl;
		system("pause");
		return 0;

	case 10:
		cout << "Type in a number.\n" << endl;
		cin >> number1;
		result = sqrt(number1);
		cout << "" << endl;
		cout << result << endl;
		system("pause");
		return 0;

	case 11:
		cout << "Type in first number.\n" << endl;
		cin >> number1;
		result = exp(number1);
		cout << "" << endl;
		cout << result << endl;
		system("pause");
		return 0;


	default:
		cout << "Please pick one of the given options" << endl;
		system("pause");
		return 0;
	}
}

int info()
{
	int a;
	cout << "please type in your age" << endl;
	cin >> a;
	cout << "your age is" << a << endl;
	system("pause");
	return 0;


}

int main() {
	char choice;
	
	cout << " _______________________ " << endl;
	cout << "|         Menu          |" << endl;
	cout << "|_______________________|" << endl;
	cout << "|  __________________   |" << endl;
	cout << "| | A for Calculator |  |" << endl;
	cout << "| |__________________|  |" << endl;
	cout << "|  __________________   |" << endl;
	cout << "| |   B for Arrays   |  |" << endl;
	cout << "| |__________________|  |" << endl;
	cout << "|  __________________   |" << endl;
	cout << "| |   C for info     |  |" << endl;
	cout << "| |__________________|  |" << endl;
	cout << "|_______________________|" << endl;
	
	cin >> choice;
	if (choice == 'a') calculator();
	else if (choice == 'c') info();
	else cout << "invalid choice\n";
	return 0;
}

[MikeyBoy]

Please use code tags when posting code, to make your code readable:

http://www.cplusplus.com/articles/z13hAqkS/

[9ypNhbRD]

done

[9ypNhbRD]

can someone help ? :(