Thread: scanf me thinks

The problem is in your 'else' statement. You don't want to recursively call your MainMenu() function on an invalid input. Try to loop back to your 1st printf statement upon an invalid input.

Try something more like this to cover for problematic input:

Code:

#include <stdio.h>

static int out_of_range ( int val, int lower, int upper )
{
  return val < lower || upper < val;
}

static int menu ( void )
{
  int option = 0;
  
  while ( out_of_range ( option, 1, 4 ) ) {
    printf ( "Please chose from the options below:\n" );
    printf ( "[1] Start\n" );
    printf ( "[2] About\n" );
    printf ( "[3] Help\n" );
    printf ( "[4] Exit\n\n" );
    
    /* Always check the return value of input functions */
    if ( scanf ( " %d", &option ) != 1 ) {
      /* Tidy up */
      int ch;

      while ( ( ch = getchar() ) != '\n' && ch != EOF )
        ;
    }
    
    if ( out_of_range ( option, 1, 4 ) )
      printf("Invalid entry, please try again.\n");
  }
  
  return option;
}

int main ( void )
{
  switch ( menu() ) {
  case 1:
    printf ( "Starting...\n" );
    break;
  case 2:
    printf ( "Menu Program -- ver. 1.00\n" );
    break;
  case 3:
    printf ( "No help available\n" );
    break;
  case 4:
    printf ( "Have a nice day!\n" );
    break;
  }
  
  return 0;
}

-Prelude