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C++ - Check input type

  • 24-03-2007 02:08PM
    #1
    bman
    Registered Users, Registered Users 2 Posts: 590 ✭✭✭


    Hey,

    I'm just wondering whats the best way to check the input from a user to ensure its an interger in C++?
    int a;
cout << "Enter an integer value: ";
cin >> a;

//Check to make sure its an integer???

    Is there some sort of type function to ensure the input is of type int?


Comments

  • #2
    markkilpatrick
    Registered Users, Registered Users 2 Posts: 31 ✭markkilpatrick


    you will need to have
    #include <ios>
    #include <limits>

    and then do this


    cin>>input;
    while(!cin)
    {
    cout<<"invalid input. Please enter an interger."<<endl;
    cin.clear();
    cin.ignore(numeric_limits<streamsize>::max(), '\n');
    cin>>input;
    }


  • #3
    bman
    Registered Users, Registered Users 2 Posts: 590 ✭✭✭bman


    Thanks. Will give that a go.


  • #4
    bman
    Registered Users, Registered Users 2 Posts: 590 ✭✭✭bman


    This works if you input a string with a non numeric character as the first letter but not if the first character is a numeric character. For example, entering 35d still gets through. In this case it seems to take 35 as the integer value.

    Any ideas on this problem?


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