Error control problem?

Question

hey everyone, i wont lie this is a school lab, but for the lab i have all the prerequisits complete, this is more a question i was wondering about because i was trying to add a little extra to it. Well i want to add a while loop saying while the answer isn't this or this or this or this then say its an error and repeat the input, but instead every time i add something i get an error and it just doesn't seem to work? I've tryed a few different ways to do this, and it all works fine with out the while loop , and if i put just one condition into the while loop, but if i put more than one condition it doesn't seem to like it? Any help would be great, thank you all in advance
import java.lang.*;
import java.util.Scanner;
public class whats_the_math {
     public static void main (String args[])
          Scanner in = new Scanner (System.in);
          String mathNumS;
          char mathNum;
               System.out.println("\nEnter one of these to see what does what!\n+, -, *, /, %\n\nEnter Exit to Finish =]");
               mathNumS = in.nextLine();
               mathNum = mathNumS.charAt(0);
//This is what im having problems with gettnig to work, the multiple conditions in the While loop. With just one condition it works fine but i cant seem to ge tit to work
// With multiple loops, if anyone could point me to some info or lend a hand that would be great because all the stuff ive foudn for while loops include just one condition
               while(mathNum != '+' || mathNum != '-' || mathNum != '*' || mathNum != '/' || mathNum != '%')
                    System.out.println("Error");
                    mathNumS = in.nextLine();
                    mathNum = mathNumS.charAt(0);
// This is where my problem stops, because with out it everything seems to work fine, so im guessing its seomthing to do with just this while loop i have because it doesnt
// seem to acknowledge the right answers and just gets stuck in the loop i guess?
                    switch(mathNum)
                         case '+':
                              System.out.println("This is Addition!\n");
                              break;
                         case '-':
                              System.out.println("This is Subtraction!\n");     
                              break;
                         case '*': case 'X':
                              System.out.println("This is multiplication!\n");
                              break;
                         case '/':
                              System.out.println("This is Division!\n");
                              break;
                         case '%':
                              System.out.println("This is modulus operation!\n");
                              break;
}

Answer 1

sorry the specific problem is, when i add the while loop, and when i add more conditions into it with the || operator, it doesnt work for me, say i put while(mathNum != '+' || mathNum != '-') and i use the switch statement afterwards like in my code i have posted, then it ignores even the right answer i put in, so its always giving me the error in the loop i added and not carrying on with the rest of the program. ill repost my code using the code button( sorry im new to the forum and didnt see it before) i commented around the part thats not working right aswell, thanks again
import java.lang.*;
import java.util.Scanner;
public class whats_the_math {
public static void main (String args[])
Scanner in = new Scanner (System.in);
String mathNumS;
char mathNum;
System.out.println("\nEnter one of these to see what does what!\n+, -, *, /, %\n\nEnter Exit to Finish =]");
mathNumS = in.nextLine();
mathNum = mathNumS.charAt(0);
//This is what im having problems with gettnig to work, the multiple conditions in the While loop. With just one condition it works fine but i cant seem to get it to work
// With multiple loops, if anyone could point me to some info or lend a hand that would be great because all the stuff ive found for while loops include just one condition
while(mathNum != '+' || mathNum != '-' || mathNum != '*' || mathNum != '/' || mathNum != '%')
System.out.println("Error");
mathNumS = in.nextLine();
mathNum = mathNumS.charAt(0);
// This is where my problem stops, because with out it everything seems to work fine, so im guessing its seomthing to do with just this while loop i have because it doesn't
// seem to acknowledge the right answers and just gets stuck in the loop i guess?
switch(mathNum)
case '+':
System.out.println("This is Addition!\n");
break;
case '-':
System.out.println("This is Subtraction!\n");
break;
case '*': case 'X':
System.out.println("This is multiplication!\n");
break;
case '/':
System.out.println("This is Division!\n");
break;
case '%':
System.out.println("This is modulus operation!\n");
break;
}