What's the run time error?

#1

import java.util.*;
public class Main {
public static void main(String args[]) {
float a,b,result;
char ch;
Scanner scn=new Scanner(System.in);
do {
System.out.println(“Enter the operation you wanna perform:”);
ch=scn.next().charAt(0);
switch(ch) {
case (’+’):
System.out.println(“Addition”);
a=scn.nextFloat();
b=scn.nextFloat();
result=a+b;
System.out.println(result);
break;

		case ('-'):
			System.out.println("Subtraction");
		    a=scn.nextFloat();
		    b=scn.nextFloat();
		    result=a-b;
		    System.out.println(result);
		    break;
		    
		case ('*'):
			System.out.print("Multiplication");
		    a=scn.nextFloat();
		    b=scn.nextFloat();
		    result=a*b;
		    System.out.println(result);
		    break;
		    
		case ('/'):
			System.out.println("Division");
		    a=scn.nextFloat();
		    b=scn.nextFloat();
		    result=a/b;
		    System.out.println(result);
		    break;
		    
		case ('X'):
			System.exit(0);
		 break;
		 default : System.out.println("Wrong Choice.....\n");
		 break;
		    
		
			}
	}
	while(ch!='X');
	
}

}

#2

@Kamyanagpal,

  1. Don’t use unnecessary print statements like : “System.out.println(“Enter the operation you wanna perform:”);”
  2. Don’t use the default condition. Use switch only when ch == ‘+’ || ch == ‘-’ || ch == ‘*’ || ch == ‘/’ || ch == ‘%’
  3. correct while statement: while(ch!=‘x’&& ch!=‘X’);