Answer Happy

Update the following calculator program so that it can handlethe power operator as well. That means, it prints 34 when the inputstring is "3^(4-1)+7"
import java.util.*;public class Calculator { private static Scanner s = newScanner(System.in); private static int getOp(String exp, int cur){ Scanner s = newScanner(exp.substring(cur)); s.useDelimiter("[^0-9]"); return s.nextInt(); } public static int doOp(int op1, int op2, charoperator) { switch(operator) { case '+': return op1+op2; case '-': return op1-op2; case '*': return op1*op2; case '/': return op1/op2; default: return 0; } } public static int comparePrecedence(char op1, charop2) { if(op1 == '+' || op1 == '-') if(op2 == '+' || op2 =='-') return0; else return-1; else if(op2 == '+' || op2 == '-') return 1; else return 0; } public static void main(String args[]) throwsException{ Stack<Character> operators = newStack<Character>(); Stack<Integer> operands = newStack<Integer>(); while(true){ System.out.println("Please entera new expression: "); String exp = s.nextLine(); if(exp.equals("DONE")) break; for(int cur = 0; cur <exp.length();cur++){ switch(exp.charAt(cur)) { case '+':case'-':case'*':case'/': while(!operators.isEmpty() && operators.peek() !='(') if(comparePrecedence(operators.peek(),exp.charAt(cur)) >= 0) { int temp = operands.pop(); operands.push(doOp(operands.pop(),temp, operators.pop())); }else break; operators.push(exp.charAt(cur)); break; case '(': operators.push(exp.charAt(cur)); break; case ')': if(operators.peek()!= '('){ int temp = operands.pop(); operands.push(doOp(operands.pop(), temp,operators.pop())); } operators.pop();//pop the matching open parenthesis break; case ' ': case'\t': break; default://ifnumber if(Character.isDigit(exp.charAt(cur))){ int temp = getOp(exp, cur); while(cur < exp.length() &&Character.isDigit(exp.charAt(cur))) cur++; cur--; operands.push(temp); }else throw new Exception("Error: bad input"); } } int result; while(!operators.isEmpty()){ int temp =operands.pop(); operands.push(doOp(operands.pop(), temp, operators.pop())); } System.out.println("The resultis " + operands.pop()); } }}