Cant figure out java while loop

Question

Public static String userMove(){
Scanner input = new Scanner(System.in);

System.out.print("Where would you like to move? (R, L, U, D)");

String selection = input.next();

while ( !selection.equalsIgnoreCase("r") || !selection.equalsIgnoreCase("l") || !selection.equalsIgnoreCase("u")||
!selection.equalsIgnoreCase("d")) {

System.out.print("Please choose either (R, L, U, D)");
userMove();
}
return selection;
}

im trying to get the test to repeat itself until either r l u or d is selected and when one of those are selected it still repeats itself over and over please help! ( userMove(); is the method its contained in to call itself )

Answer 1

// Alternative using contains method
public static String userMove(){
Scanner input = new Scanner(System.in);
System.out.print("Where would you like to move? (R, L, U, D)");
String selection = input.next();
// Here we check if 'selection' is a substring of "rlud".
// I guess this is somewhat more readable.
while(!"rlud".contains(selection.toLowerCase()))
{
System.out.println("Please choose either (R, L, U, D)");
selection = input.next();
}
return selection;
}

Answer 2

could you post your code here so we can see exactly what is happening? that would be the easiest.

Answer 3

Nick Johnson the condition you passed to the while loop was incorrect, and you call UserMove again inside loop body. I would rather suggest to re-read the 'selection' input inside loop body, as follows;

public static String userMove(){
Scanner input = new Scanner(System.in);
System.out.print("Where would you like to move? (R, L, U, D)");
String selection = input.next();
// Use the ! operator only in the beginning, not on each operand
while (!(selection.equalsIgnoreCase("r") || selection.equalsIgnoreCase("l") || selection.equalsIgnoreCase("u") || selection.equalsIgnoreCase("d"))) {
System.out.print("Please choose either (R, L, U, D)");
// Here read the 'selection' input again, instead of calling UserMove
selection = input.next();
}
return selection;
}

Answer 4

I got the alternative one to work but for some reason with the other one the only one that would work is if i selected "r" if not, it would forever just keep asking for input

Answer 5

Nick Johnson Sorry mate, I forgot to wrap the conditions in parentheses, I'll update the first alternative now, my bad :D

Answer 6

I updated so the full method is there now.