Where is the error in my code it is showing exception

#1

import java.util.*;
public class Main {
public static void main(String[] args) {
Scanner sc=new Scanner(System.in);
int a=0,b=0,c=0;
char ch=0;
do {
a=sc.nextInt();
b=sc.nextInt();
ch=sc.next().charAt(0);
if (ch == ‘+’) {
c = a + b;
System.out.println(c + " ");
} else if (ch == ‘-’) {

                c = a - b;
                System.out.println(c + " ");
            } else if (ch == '*') {
                

                c = a * b;
                System.out.println(c + " ");
            } else if (ch == '/') {
                
                c = a / b;
                System.out.println(c + " ");
            } else if (ch == '%') {
                
                c = a % b;
                System.out.println(c + " ");
            } else if (ch >= 58 && ch <= 64) {
                System.out.println("Invalid operation. Try again.");
            }
        }while(ch!='x' && ch!='X');
        sc.close();
    }
}
#2

We first need to the input a character.
If ch is among ‘+’, ‘-’, ‘*’, ‘/’ or ‘%’ then only we need to take the input a and b.
So take the input a and b inside the if conditions.

#3

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