Learning switch and function call returns

[dithanial]

Hello all. I'm trying to make a menu loop by using while (function != 0) function(); I'm returning a value of 0 for my exit command but it goes through my exit routine and starts back over, not exiting... all other menu options are working fine and loop properly.

On the switch, case 4 is the one I'm having a problem with. I even changed the function to an int and made a cout to get the return value and it was bringing a 0, yet the main function continued looping one last time. If I chose 4 twice in a row, it would exit.

I'm new here, and I'm not sure if posting my entire code is considered rude or something, so I hope you'll forgive me if it is.

			
#include <iostream>
#include <cmath>
#include <iomanip>
#include <Windows.h>
#include <cstdlib>

using namespace std;

const double PI = 3.14159;


				//Calculation functions

double circle_calc(float x)
{
	return (PI * pow(x, 2.0));
}

float rectangle_calc(float x, float y)
{	
	return (x * y);
}

float triangle_calc(float x, float y)
{
	return (x * y * .5);
}


				//Organizes user's choice

int circle()			//user chooses circle
{
	float radius;
	cout << "Please enter the radius of the circle: \n" <<
		fixed << showpoint << setprecision(2);
	cout << "Radius: ";
	cin >> radius;

	if (radius < 0)
	{
		cout << "Please enter a valid number.\n";
		system("pause");
		return 1;
	}

	else
	{
		cout << "The area of this circle is: " << circle_calc(radius) << endl;
		system("pause");
		system("cls");
		return 0;
	}
}

int rect()			//user chooses rectangle
{
	float length, width;
	cout << "Please enter the lenth and width of the rectangle: \n" <<
		fixed << showpoint << setprecision(2);
	cout << "Length: ";
	cin >> length;
	cout << "\nWidth: ";
	cin >> width;

	if (length < 0)
	{
		cout << "Please enter a valid number.\n";
		system("pause");
		return 1;
	}

	else if (width < 0)
	{
		cout << "Please enter a valid number.\n";
		system("pause");
		return 1;
	}

	else cout << "The area of this rectangle is: " << rectangle_calc(length, width) << endl;

	system("pause");
	system("cls");
	return 0;
}

int tri()			//user chooses triangle
{
	float length, width;
	cout << "Please enter the lenth and width of the triangle: \n" <<
		fixed << showpoint << setprecision(2);
	cout << "Length: ";
	cin >> length;
	cout << "\nWidth: ";
	cin >> width;

	if (length < 0)
	{
		cout << "Please enter a valid number.\n";
		system("pause");
		return 1;
	}

	else if (width < 0)
	{
		cout << "Please enter a valid number.\n";
		system("pause");
		return 1;
	}

	else cout << "The area of this triangle is: " <<
		triangle_calc(length, width) << endl;

	system("pause");
	system("cls");
	return 0;
}

				//exit functions chosen randomly

void exit_func1()			//exits with flair!
{
	int exit_loop = 10, exit_switch;

	while(exit_loop >= 0)
	{
		int exit_col = 0;

		cout << setw(20) << right << " ";
		switch(exit_loop)
			{
			case 0 : cout << " ";
			case 1 : cout << " ";
			case 2 : cout << " ";
			case 3 : cout << " ";
			case 4 : cout << " ";
			case 5 : cout << " ";
			case 6 : cout << " ";
			case 7 : cout << " ";
			case 8 : cout << " ";
			case 9 : cout << " ";
			case 10 : cout << " ";
			}

		while (exit_col <= exit_loop)
			cout << right << exit_col++ << " ";
		
		cout << endl;
		exit_loop--;
		Sleep(500);
	}
	Sleep(2000);
}

void exit_func2()			//exits with flair!
{
	int exit_loop = 10, exit_switch;

	//loop columns
	while(exit_loop >= 0)
	{
		int exit_col = 0;

		cout << setw(20) << right << " ";
		switch(exit_loop)
			{
			case 0 : cout << ". . . . . . . . . . .";
				break;
			case 1 : cout << ". . . . . . . . . .";
				break;
			case 2 : cout << ". . . . . . . . .";
				break;
			case 3 : cout << ". . . . . . . .";
				break;
			case 4 : cout << ". . . . . . .";
				break;
			case 5 : cout << ". . . . . .";
				break;
			case 6 : cout << ". . . . .";
				break;
			case 7 : cout << ". . . .";
				break;
			case 8 : cout << ". . .";
				break;
			case 9 : cout << ". .";
				break;
			case 10 : cout << ".";
				break;
			}

		while (exit_col <= exit_loop)
			cout << right << exit_col++ << " ";
		
		cout << endl;
		exit_loop--;
		Sleep(500);
	}
	Sleep(2000);
}

void exit_func3()			//exits with flair!
{
	int exit_loop = 10, exit_switch;

	//loop columns
	while(exit_loop >= 0)
	{
		int exit_col = 0;

		cout << setw(20) << right;

		while (exit_col <= exit_loop)
		{
			switch(exit_loop)
			{
			case 0 : cout << "           ";
				break;
			case 1 : cout << "          ";
				break;
			case 2 : cout << "         ";
				break;
			case 3 : cout << "        ";
				break;
			case 4 : cout << "       ";
				break;
			case 5 : cout << "      ";
				break;
			case 6 : cout << "     ";
				break;
			case 7 : cout << "    ";
				break;
			case 8 : cout << "   ";
				break;
			case 9 : cout << "  ";
				break;
			case 10 : cout << " ";
				break;
			}

			cout << right << exit_col++ << " ";
		}
		cout << endl;
		exit_loop--;
		Sleep(500);
	}
	Sleep(2000);
}


void exit_func()			//randomly chooses which exit function you see.
{
	int randnum, low = 1, high = 100;

	srand(time(0));
	randnum = (rand() % (low - high + 1)) + low;

	cout << randnum;
	Sleep(500);
	cout << "\b\b  \n";
	if (randnum >= 67)
		exit_func1();
	else if (randnum > 33 && randnum < 67)
		exit_func2();
	else exit_func3();
}


				//prompts user for desired function
int user_choice()
{
	int choice;
	
	for (int x = 0; x < 25; x++)
		cout << "* ";
	cout << endl <<
		"*\tPlease Choose your desired function:\t*\n" << 
		"* 1. Calculate the Area of a Circle\t\t*\n" <<
		"* 2. Calculate the Area of a Rectangle\t\t*\n" <<
		"* 3. Calculate the Area of a Triangle\t\t*\n" <<
		"* 4. Quit \t\t\t\t\t*\n";
	for (int x = 0; x < 25; x++)
		cout << "* ";
	cout << endl <<	"\n\tEnter Your Choice (1-4):\t";
	cin >> choice;

	switch(choice)			//Actual choice function
	{
		case 1 :			//If the user chooses circle.
		{
			cout << "You chose " << choice << "!\n\t";		
			circle();
			cin.clear();
			system("cls");
			return 1;
		}	
		break;

		case 2 :			//If the user chooses rectangle
		{
			cout << "You chose " << choice << "!\n\t";
			rect();
			cin.clear();
			system("cls");
			return 1;
		}
		break;

		case 3 :			//If the user chooses triangle
		{
			cout << "You chose " << choice << "!\n\t";
			tri();
			cin.clear();
			system("cls");
			return 1;
		}
		break;

		case 4 :			//If the user chooses to quit
		{
			cout << "Thanks for using my program!!!\n\t";
			cin.clear();
			exit_func();
			return 0;
		}
		break;

		default:			//If the user chooses an invalid option
		{
			cout << "please choose 1 through 4...\n\t";
			cin.clear();
			system("pause");
			system("cls");
			return 1;
		}
		break;
	}
}


int main()
{
	while (user_choice() != 0)	
		user_choice();
		

	return 0;
}

[Yanson]

try this

int main()
{
	while (user_choice() != 0);
		
	return 0;
}

[dithanial]

Apparently I missed some fundamental part of the While statement. Yanson, your response works perfectly, thank you very much!

Dithanial.