Issue with input validation

[stormbot]

In this part of the program, I am asking the user to select an option from the menu. The only acceptable input should be 1, 2, or 3. The validation is working fine... except when the user enters a character that is not a number. For example, if you enter "f", the program spams the validation statement infinitely. How can I make my program handle unexpected input in this way?

// Unit 4 Assignment.cpp : Defines the entry point for the console application.
//

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


int main()
{

	double userPackage;
	cout << "\n\t\tWhich package did you purchase? (Please enter 1, 2, or 3)\n"
		<< "1. Package A\n"
		<< "2. Package B\n"
		<< "3. Package C\n\n"
		<< "Please enter your package: ";
	cin >> userPackage;

	while (userPackage != 1 && userPackage != 2 && userPackage != 3)
	{
		cout << "Please enter 1, 2, or 3: ";
		cin >> userPackage;
	}

	int gigs;
	cout << "How many gigabytes were used?";
	cin >> gigs;

	if (userPackage == 1)
		userPackage = 39.99 + (gigs - 4) * 10;
	else if (userPackage == 2)
		userPackage = 59.99 + (gigs - 8) * 5;
	else userPackage = 69.99;
	
	cout << "Your monthly total is: $" << userPackage << endl;

    return 0;
}

[fiji885]

You can do this

int myInt;
std::cin >> myInt;
if(std::cin.fail()) // In abstract, this is basically checking if the previous input matches
{                      // what was suppose to be inputted (i.e. a character input for an int data type)
                        // If it DOES NOT, then perform the following actions...
    std::cin.clear(); // Clear the input stream
    std::cin.ignore(99999, '\n'); // Ignore the rest of the input.
}

Now you need to figure out how to incorporate this into your program.

[stormbot]

Can anyone else help me with this?

[lastchance]

Have you tried the perfectly good solution that @fiji885 demonstrated for you?
- change your input variable expecting 1, 2 or 3 to an int?
- check the state of the stream for invalid input;
- clear any failed state and remove anything left in the input buffer.
Seems a good solution to me.