Questions and Exercises: Operators

Questions

  • Consider the following code snippet.
arrayOfInts[j] > arrayOfInts[j+1]

Which operators does the code contain?

  • Consider the following code snippet.
int i = 10;
int n = i++%5;
  • What are the values of i and n after the code is executed?

    • What are the final values of i and n if instead of using the postfix increment operator ( i++ ), you use the prefix version ( ++i) )?
  • To invert the value of a boolean , which operator would you use?

  • Which operator is used to compare two values, = or == ?

  • Explain the following code sample: result = someCondition ? value1 : value2;

Exercises

  • Change the following program to use compound assignments:
class ArithmeticDemo {

     public static void main (String[] args){
          
          int result = 1 + 2; // result is now 3
          System.out.println(result);

          result = result - 1; // result is now 2
          System.out.println(result);

          result = result * 2; // result is now 4
          System.out.println(result);

          result = result / 2; // result is now 2
          System.out.println(result);

          result = result + 8; // result is now 10
          result = result % 7; // result is now 3
          System.out.println(result);
     }
}
  • In the following program, explain why the value "6" is printed twice in a row:
class PrePostDemo {
    public static void main(String[] args){
        int i = 3;
        i++;
        System.out.println(i);    // "4"
        ++i;                     
        System.out.println(i);    // "5"
        System.out.println(++i);  // "6"
        System.out.println(i++);  // "6"
        System.out.println(i);    // "7"
    }
}

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