Trail: Learning the Java Language
Lesson: Language Basics
Questions and Exercises
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Questions and Exercises: Operators

Questions

  1. Consider the following code snippet.
    arrayOfInts[j] > arrayOfInts[j+1]
    
    Which operators does the code contain?
  2. Consider the following code snippet.
    int i = 10;
    int n = i++%5;
    
    1. What are the values of i and n after the code is executed?
    2. What are the final values of i and n if instead of using the postfix increment operator (i++), you use the prefix version (++i))?
  3. To invert the value of a boolean, which operator would you use?
  4. Which operator is used to compare two values, = or == ?
  5. Explain the following code sample: result = someCondition ? value1 : value2;

Exercises

  1. 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);
         }
    }
    
    
  2. 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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