Loop if i input letters or special characters

Question

I don't know what happened but everytime I put Letters and Special Characters It loops insanely, and I dont know how to correct it. It is i think from the claude part.

#include<iostream>
using namespace std;
    int main()
    {
        int a,b;
    Claude:
    {
    cout<<"Please Enter Your Pin: ";
    cin>>a;
    cout<<endl;
    system("cls");
    cin.get();
    }

        if(a==1234)
    {       Josh:
           cout<<"Choose An Option: "<<endl;
           cout<<"1: Withdraw                 2: Check Balance";
           cout<<endl;
           cout<<"3: Deposit                  4: Exit";
           cout<<endl;
          cout<<"Enter Here: ";
          cin>>b;
          system("cls");
    }
    else
        {
        cout<<"Incorrect Pin, Please Try Again"<<endl;
        cout<<endl;
        cout<<"Press Any Key To Continue "<<endl;
        system("pause>nul");
        system("cls");
        goto Claude;


    }

      if(b==1)
        {
        cout<<"How Much: ";

        }
    else if (b==2)
        {
        cout<<"2000.00";

        }
    else if(b==3)
        {
        cout<<"Nothing To Withdraw";

        }
    else if(b==4)
        {
        cout<<"test";
        }   
    else
        {
            cout<<"Please Enter Valid Input, Press Any Key To Continue ";
            cin.get();
            system("cls");
            goto Josh;  
        }


    return 0;   
    }

The code is working without error and working properly. Please look for the result in your own dev C++.

Remove the extra parentheses that are not needed and makes your code much more unreadable — Crazy Psychild, Sep 06 '15 at 13:42
Recommendation: do not use goto (http://stackoverflow.com/questions/3517726/what-is-wrong-with-using-goto) — CIsForCookies, Sep 06 '15 at 13:44
could you please suggest other code for goto i don't know the substitute for that — XD Joshua Claude, Sep 06 '15 at 13:47
When `cin>>a` fails (by encountering a character that cannot be parsed as part of an integer), a `failbit` is set on the stream. As long as this bit is set, all subsequent operations on this stream fail immediately. See also: [clear()](http://en.cppreference.com/w/cpp/io/basic_ios/clear) — Igor Tandetnik, Sep 06 '15 at 13:50
@XDJoshuaClaude What about stepping through your code with the debugger, to see what's actually going on? — πάντα ῥεῖ, Sep 06 '15 at 14:08

mksteve · Accepted Answer · 2015-09-06T14:09:09.260

1

When you type 'a', there is nothing to eat the input. This will keep failing, going "insane"

cin >> a;

Reads numbers into a. If it is unable to read, then it sets an error and reads nothing.

edited Sep 06 '15 at 14:09

answered Sep 06 '15 at 14:00

mksteve

12,614
3
28
50

didn't get it, all i know is that when i input letter it malfunctions – XD Joshua Claude Sep 06 '15 at 14:52

score 1 · Answer 2 · answered Sep 06 '15 at 14:06

1

You have to clear your console input buffer (std::cin).

You can do that with cin.clear() and cin.ignore()

//...
cout<<endl;
cout<<"Press Any Key To Continue "<<endl;

cin.clear( );
cin.ignore( 10000, '\n' );
//...

answered Sep 06 '15 at 14:06

Clemens Susenbeth

56
2
2

i write that part but it doesnt clear the previous output – XD Joshua Claude Sep 06 '15 at 14:27

rewrihitesh · Answer 3 · 2015-09-06T15:15:21.727

it happens when your reentered in to Josh goto statement and cin>>b doesn't take input because of previous value in inputstream So, just clear the inputstream by calling cin.ignore();

#include<iostream>
#include<limits>
    using namespace std;
    int main()
    {
        int a,b;
    Claude:
    {
    cout<<"Please Enter Your Pin: ";
    cin>>a;
    cout<<endl;
    system("cls");
    cin.get();
    }

        if(a==1234)
        {
         Josh:

           cout<<"Choose An Option: "<<endl;
           cout<<"1: Withdraw                 2: Check Balance";
           cout<<endl;
           cout<<"3: Deposit                  4: Exit";
           cout<<endl;
           cout<<"Enter Here: ";
           //cin.ignore(numeric_limits<streamsize>::max(),'*');
           cin>>b;

          system("cls");
    }
    else
        {
        cout<<"Incorrect Pin, Please Try Again"<<endl;
        cout<<endl;
        cout<<"Press Any Key To Continue "<<endl;
        system("pause>nul");
        system("cls");
        goto Claude;


    }

      if(b==1)
        {
        cout<<"How Much: ";

        }
    else if (b==2)
        {
        cout<<"2000.00";

        }
    else if(b==3)
        {
        cout<<"Nothing To Withdraw";

        }
    else if(b==4)
        {
        cout<<"test";
        }   
    else
        {
            cout<<"Please Enter Valid Input, Press Any Key To Continue ";





        cin.clear();
        cin.ignore();



        cin.get();
        cin.get();

        system("cls");
        goto Josh;  
        }


    return 0;   
    }

it still loops when i input letters – XD Joshua Claude Sep 06 '15 at 14:50 — XD Joshua Claude, Sep 06 '15 at 14:50

Loop if i input letters or special characters

3 Answers3