Entering valid user input!

[frank1234]

Entering valid user input?



Hello guys; I am wondering if you can help me.
How can I write my simple program so if the user enters an invalid number,
The program won’t exit? I know I am supposed to use a if (cin) or if (!cin),
But I don’t know where in the program or how I should use it. Right now my
Program looks kind of like this:
If (number > 1 && number < 1001)
Go through some function loops
Else
Cout << “invalid number”;
I need to write it so when the user enters an invalid number, the program
Would Keep asking for the right number until it's given.
Thanks guys.

[buffbill]

You could use some thing as explicit as this:

do
{
//other code and warnings go here

}while(number<1 && number>1000);

[Smac89]

if(cin.good())
{
//
//
}
else
{
cin.ignore();
cin.clear();
cout << "Invalid input!\n";
}

[cire]

#include <iostream>
#include <string>
#include <limits>

int getNum( const std::string& prompt,  int min, int max )
{
    int input ;

    std::cout << prompt << "\n> " ;

    while ( !(std::cin >> input)  ||  (input < min || input > max) )
    {
        // clear error state and remove rest of the line.
        std::cin.clear() ; 
        std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n') ;

        std::cout << "Invalid input!\n" << prompt << "\n> " ;
    }
   

    return input ;
}


int main()
{
    int num = getNum("Enter a number between 10 and 100", 10, 100) ;
    std::cout << "You entered " << num << "!\n" ;
}