Re: Switch inside While loop... User error!

From:
Kai-Uwe Bux <jkherciueh@gmx.net>
Newsgroups:
comp.lang.c++
Date:
Sun, 11 Feb 2007 20:35:53 -0500
Message-ID:
<eqog9q$o4t$1@murdoch.acc.Virginia.EDU>
Cybex wrote:

I am trying to get this to work but when ever I enter an proper
integer it just hangs. The Switch default seems to catch the improper
integers but the right ones are not triggering the way I thought they
would.

Any help would be appreciated...

#include <iostream>
#include <string>
using namespace std;

int main()
{
     //declare variables
     int intEmpID = 0;
     string strEmpName = "";

     //Gather inputs
     cout << "Enter the emplyee's ID: ";
     cin >> intEmpID;

     while (intEmpID >0) {
          switch (intEmpID) {
               case 1234:
                    strEmpName = "Sue Nguyen";
                    break;


This break just exits the switch stament. It does not exit the ambient while
loop.

               case 1345:
                    strEmpName = "Janice Blackfeather";
                   break;
               case 3456:
                    strEmpName = "Allen Kraus";
                    break;
               case 4567:
                    strEmpName = "Margie O'Donnell";
                    break;
               default :
                    cout << "Incorrect ID - Please try again" <<"\n";
                    cout << "Re-enter the emplyee's ID: ";
                    cin >> intEmpID;
          } //End switch
     } // End while

     //display outputs
     cout << "The employee ID " << intEmpID << " belongs to: " <<
strEmpName << " \n \n";
     cout << "Enter the next emplyee's ID: ";
     cin >> intEmpID;

     return 0;
} //end of main function

Possible fixes include:

a) Use of a boolean flag.
b) Use of goto.
c) Use of a function, e.g.:

#include <iostream>
#include <string>
using namespace std;

std::string get_name ( int & intEmpID ) {
  while ( true ) {
    cout << "Enter the emplyee's ID: ";
    cin >> intEmpID;
    switch (intEmpID) {
    case 1234:
      return( "Sue Nguyen" );
    case 1345:
      return( "Janice Blackfeather" );
    case 3456:
      return( "Allen Kraus" );
    case 4567:
      return( "Margie O'Donnell" );
    default :
      cout << "Incorrect ID - Please try again" <<"\n";
    }
  }
}

int main()
{
     //declare variables and get id:
     int intEmpID = 0;
     string strEmpName = get_name( intEmpID );

     //display outputs
     cout << "The employee ID " << intEmpID << " belongs to: " <<
strEmpName << " \n \n";
     cout << "Enter the next emplyee's ID: ";
     cin >> intEmpID;

     return 0;
} //end of main function

Note that this is not totally satisfying since the function has too many
responsibilities; it looks up the string value and it issues requests for
changing the ID. It might be better to have a std::map<int,std::string>
that matches id-numbers and names and then the input validation could just
check whether that map has an entry with a given id-number.

Best

Kai-Uwe Bux

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