Trouble with looping a function

[Almrls]

With the following code:

#include <iostream>

using namespace std;
bool key = true;
char swit;

void cont(char ans)
{
	switch (ans)
	{
			case 'y': 
				break;
			case 'n': 
				cout <<"Goodbye\n";
				key = false;
				break;
			default: 
				cout <<"Derp\n";
				key = false;
				break;
	}
}

int fact(int xx)
{
	int Fact(1);
	for (int i = 1; i <= xx; i++)
		Fact *= i;
	return Fact;
}

void main()
{
	int x;
	while (key = true)
	{
		cout <<"Enter an integer up to 10: "; cin >> x;
		if (x > 10)
			cout <<"Invalid input.\n";
		else if (x > -1)
			cout <<"Factorial of "<< x <<" = "<< fact(x) <<"\n";
		else
			cout <<"Invalid input.\n";
		cout <<"\nContinue? (y/n): "; cin >> swit; cout <<"\n";
		cont(swit);
	}
}

I get the following output:

Enter an integer up to 10: 11
Invalid input.

Continue? (y/n): y

Enter an integer up to 10: 0
Factorial of 0 = 1

Continue? (y/n): y

Enter an integer up to 10: -1
Invalid input.

Continue? (y/n): n

Goodbye
Enter an integer up to 10: -1
Invalid input.

Continue? (y/n): h

Derp
Enter an integer up to 10:

I want it to print the "Goodbye" and "Derp" messages like it does, but then end the program afterwards. Can someone please help me correct it? Thank you.

[Yanson]

Line 35 while (key = true) this is an assignment statement, not an equality statement. So this will allways evaluate to true. I would just go with this while (key)

[Almrls]

Removing = true worked. Thanks so much.