// Restrict.cmm   Allow user to only enter commands from the list provided here.

Count = 0;
Valid[Count++] = "dir"
Valid[Count++] = "chkdsk"
Valid[Count++] = "type"
Valid[Count++] = "cd"
Valid[Count++] = "set"
Valid[Count++] = "IsItFri"
Valid[Count++] = "DiskFree"


main()
{
   while ( True ) {  // True is always true, and so this will loop forever
      ShowAvailableCommands()
      Command = GetCommand()
      // check if this command is in our list
      for ( i = 0; i < Count; i++ ) {
         if ( !strcmpi(Command.Root,Valid[i]) )
            break
      }
      if ( i < Count ) {
         system(Command.Full)
      } else {
         // The command was not found
         printf("\"%s\" is not an available command!\a\n",Command.Root)
      }
   }
}

ShowAvailableCommands()
{
   printf("\nYour available commands are:\n")
   for ( i = 0; i < Count; i++ )
      printf("%s\t",Valid[i])
}

GetCommand()   // Get command from user, return a structure with two elements
               //  .Root   root name of the command entered
               //  .Full   complete line of input as entered
{
   printf("\nWhaddya want? ")
   input.Full = gets()
   // now figure out what the root was, first copy all of input, then remove space from
   // beginning, then go to first space character
   strcpy(input.Root,input.Full)
   // then remove andy whitespace from beginning of command
   while( input.Root[0] != 0  &&  isspace(input.Root[0] ) )
      input.Root++
   // end this string at the first whitespace character
   for ( c = input.Root; c[0] != 0  &&  !isspace(c[0]); c++ ) ;
   c[0] = 0
   return(input)
}