OOP-JAVA Practical 13

• PPS(C)
• JAvA

• Aim: Write a program for calculator to accept an expression as a string in which the operands and operator are separated by zero or more spaces. For ex: 3+4 and 3 + 4 are acceptable expressions.
• Code:

  import java.util.Scanner;
  public class practical13 {
      public static void main(String[] args) {
          Scanner s = new Scanner(System.in);
          System.out.print("Enter Expression :");
          String str = s.nextLine();
          String a = str.replaceAll(" ", "");
          s.close();
          if(a.length() < 3){
              System.out.println("Enter valid Expression");
          System.exit(0);
          }
          int result=0;
          int i=0;
          while (a.charAt(i)!= '+' && a.charAt(i)!='-' && a.charAt(i)!='*' && a.charAt(i)!= '/') {
              i++;
          }
          switch (a.charAt(i)) {
              case '+':
                  result=Integer.parseInt(a.substring(0, i))+Integer.parseInt(a.substring(i+1, a.length()));
                  break;
              case '-':
                  result=Integer.parseInt(a.substring(0, i))-Integer.parseInt(a.substring(i+1, a.length()));
                  break;
              case '*':
                  result=Integer.parseInt(a.substring(0, i))*Integer.parseInt(a.substring(i+1, a.length()));
                  break;
              case '/':
                  result=Integer.parseInt(a.substring(0, i))/Integer.parseInt(a.substring(i+1, a.length()));
                  break;
              default:
                  System.out.println("Enter Valid Operator");
                  break;
          }
          System.out.println(a+"="+result);
      }
  }

• Output:
  

Practical 12 Practical 14