Video-game Progamming project [help]

Hello codeGuru,
This is my first post, so I figure I would start by saying Hello. I'm a student at Auburn University in a C++ class, and I've come here to get some advice as I am new to the C language. I'm almost done with my project, which is a text based video game. I currently have 4 classes to run this program. Player, Hall, Menu and Engine. The class Menu is a class to display the options available in the menu based game, and return the value entered by the user. Currently, if you enter a value that is not a integer it will set the value of menuChoice to a char or string and then menuChoice can't be reset to an int. I can't figure out why my function isn't looping until the input I enter is valid. Here is a snippit of my code so you can get an idea of whats going on:

bool Menu::isValidInput(int input)
{
return input > 0 && input < 6;
}

int Menu::gameMenu()
{
int menuChoice = 0;

cout << "1) Move (takes time, could be risky...) " << endl;
cout << "2) Read technical papers (boost intelligence, takes time) " << endl;
cout << "3) Search for loose change (boost money, takes time) " << endl;
cout << "4) View Character " << endl;
cout << "5) Quit the game " << endl;
cout << "\nPlease choose an action: ";
do
{
cin >> menuChoice;
}
while(isValidInput(menuChoice) == false);
return menuChoice;
}

I've tried using cin.clear(); cin.sync(); along with various other cin methods and nothing works. I think it's because menuChoice is declared an int and if the user inputs a char like 'z' whenever menuChoice is set to a char it can't be reset to a int??