Operators in Java ICSE Class 10 Computer Applications

What Operators in Java is about

Weightage: CISCE publishes no chapter weightage. Section A (40 marks) is compulsory: 1-mark MCQs and 2-mark short answers including output and error questions; in Section B you answer any four of six 15-mark programming questions written in Java.Source: CISCE ICSE Computer Applications (661) specimen paper structure for 2027

Key concepts

Forms and types of operators

Forms (by number of operands):
Unary - one operand: ++a, --a, a++, a--, -a, !flag
Binary - two operands: a + b, a > b, a && b
Ternary - three operands: condition ? value1 : value2

Types:
Arithmetic: + - * / % (% gives the remainder: 17 % 5 = 2; with int operands / gives the quotient: 17 / 5 = 3)
Relational (result boolean): < > <= >= == !=
Logical (on boolean values): && (AND), || (OR), ! (NOT)
Assignment: =
Shorthand (compound assignment): += -= *= /= %= (a += 5 means a = a + 5)
Increment and decrement: ++ and --
Conditional (ternary): ?:

Note: = assigns; == compares.

Worked example

(2 marks) Classify as unary, binary or ternary: (a) !found (b) x % y (c) (a > b) ? a : b (d) count++

Try it first, then show the solutionSolution

1. (a) unary; (b) binary - 1 mark.
2. (c) ternary; (d) unary - 1 mark.

Answer: (a) unary (b) binary (c) ternary (d) unary

Prefix and postfix increment and decrement

Prefix (++a, --a): change then use: the variable is changed first and the new value is used in the expression.
Postfix (a++, a--): use then change: the old value is used in the expression and the variable is changed afterwards.

Example: int a = 5; int b = a++ + ++a;
a++ gives 5 (a becomes 6); ++a makes a 7 and gives 7; b = 5 + 7 = 12; finally a = 7.

Alone as a statement (a++; or ++a;) both simply add 1.

Worked example

(2 marks) int p = 3, q = 4; int r = p++ * q-- + --p; Find r, p and q.

Try it first, then show the solutionSolution

1. p++ gives 3 (p = 4); q-- gives 4 (q = 3); 3 × 4 = 12 - 1 mark.
2. --p makes p 3 and gives 3; r = 12 + 3 = 15 - 1 mark.

Answer: r = 15, p = 3, q = 3

Precedence and associativity

Precedence decides which operator is applied first; associativity decides the order among operators of equal precedence. From highest to lowest (syllabus operators):
1. Postfix: a++ a--
2. Unary: ++a --a, unary -, !
3. Multiplicative: * / % (left to right)
4. Additive: + - (left to right)
5. Relational: < > <= >=
6. Equality: == !=
7. Logical AND: &&
8. Logical OR: ||
9. Ternary: ?: (right to left)
10. Assignment: = += -= *= /= %= (right to left)

Because * / % share a level, they are done left to right: 42 / 6 % 2 = 7 % 2 = 1 (not 42 / 0). Brackets override precedence.

Compound assignment rule: in x += expr, Java takes the current value of x first, then evaluates expr, then stores x + expr. With x = 4: x += x++ * ++x % 2 → saved x = 4; x++ gives 4 (x = 5); ++x gives 6; 4 × 6 = 24; 24 % 2 = 0; x = 4 + 0 = 4.

Worked example

(1 mark) The output of 42 / 6 % 2 is:
(a) 1
(b) 10
(c) 2
(d) 0

Try it first, then show the solutionSolution

1. / and % have equal precedence, so left to right: 42 / 6 = 7; 7 % 2 = 1.

Answer: (a) 1

Logical operators, ternary operator, counters and accumulators

Logical operators combine conditions: (a > b && a > c) is true only if both are true; (x < 0 || x > 100) is true if either is true; !(a == b) reverses the result. && and || are short-circuit: if the left side of && is false (or of || is true), the right side is not evaluated.

Ternary operator: variable = (condition) ? valueIfTrue : valueIfFalse;
Example: int max = (a > b) ? a : b;
Nested: int big = (a > b) ? ((a > c) ? a : c) : ((b > c) ? b : c);

Counter: a variable that counts how many times something happens, increased by 1: count++ (initialised to 0).
Accumulator: a variable that adds up (accumulates) values: sum += n (initialised to 0; a product accumulator starts at 1).

Worked example

(2 marks) Rewrite using the ternary operator:
if (marks >= 40)
result = "Pass";
else
result = "Fail";

Try it first, then show the solutionSolution

1. Condition first, then ? true value : false value - 1 mark.
2. result = (marks >= 40) ? "Pass" : "Fail"; - 1 mark.

Answer: result = (marks >= 40) ? "Pass" : "Fail";

new operator, dot operator and output statements

new operator: allocates memory dynamically (at run time) for an object or array and returns its reference: Student s = new Student(); int arr[] = new int[10];

Dot operator (.): accesses members of a class or object: s.display(); Math.sqrt(16); System.out.println(); obj.marks.

Output: System.out.print(x) prints x and stays on the same line; System.out.println(x) prints x and moves to the next line. + inside the brackets joins strings: System.out.println("Sum = " + (a + b)); The brackets around a + b make it add before joining; without them "Sum = " + a + b joins a and b as text.

Worked example

(2 marks) int a = 3, b = 4; give the output of:
System.out.println("Sum = " + a + b);
System.out.println("Sum = " + (a + b));

Try it first, then show the solutionSolution

1. First line: "Sum = " + 3 gives "Sum = 3", then + 4 gives "Sum = 34" - 1 mark.
2. Second line: brackets add first: 7 - 1 mark.

Answer: Sum = 34
Sum = 7

Writing Java expressions

To turn a formula into Java: put * for every multiplication (2ab → 2 * a * b), bracket numerators and denominators ((a + b) / (2 * a * b)), and use Math methods for powers and roots (Math.pow(x, 3), Math.sqrt(x)), and Math.abs for |x|.

Examples:
(a + b) / (2ab) → (a + b) / (2 * a * b)
ut + ½at² → u * t + 0.5 * a * t * t (or 1.0 / 2 * a * t * t; note 1 / 2 is 0 in integer division)
|a + b| / √(a² + b²) → Math.abs(a + b) / Math.sqrt(a * a + b * b)

Worked example

(2 marks) Write the Java expression for s = ut + ½at².

Try it first, then show the solutionSolution

1. Every product needs *; t² as t * t - 1 mark.
2. ½ must not be written 1 / 2 (that is 0): use 0.5 - 1 mark.

Answer: s = u * t + 0.5 * a * t * t;

Operators in Java in real life

Each concept, met in an everyday situation. Read the situation, answer the question in your own words, then compare with the model answer. The one-line hook is what to remember.

Topics in this chapter

• Increment, Decrement, Shorthand Operators and Precedence

Operators in Java: syntax and key facts

Precedence ladder

1. 1.postfix
2. 2.prefix/unary/!
3. 3.* / %
4. 4.+ −
5. 5.< > <= >=
6. 6.== !=
7. 7.&&
8. 8.||
9. 9.?:
10. 10.= += −= …

Equal levels: left to right (assignment and ternary: right to left).

Increment rules

a++ / a--: use then change; ++a / --a: change then use

In x += e, x's old value is saved first.

Ternary

var = (condition) ? valueIfTrue : valueIfFalse;

Integer arithmetic

17 / 5 = 3, 17 % 5 = 2; −17 % 5 = −2

Sign of % follows the left operand.

How the board asks Operators in Java

The question patterns to expect, and the method that works for each.

Tricks to remember Operators in Java

Short memory aids. Say each one aloud once, then use it on a question the same day.

• PUMA RELATES

  Postfix, Unary, Multiplicative, Additive, RELational, Equality, AND, OR (Ternary), Assignment last.

  Use it when: Precedence order.

• Plus before = change first

  When ++ comes before the name, the change comes before the use.

  Use it when: Prefix vs postfix.

Operators in Java: board-level solved questions

Ordered from board level to HOTS. Cover the solution, write your own, then compare step by step.

Case-study practice (Section B style)

Read the situation, then answer every part. In the board paper this is a 10-mark question split into 2 + 3 + 5 marks.

Where the marks are

How a typical answer is split into step marks. Show every step: a right final answer alone rarely earns full marks.

Where students lose marks in Operators in Java

The slips examiners see most often, and what to write instead.

• ✗Mistake: Evaluating by BODMAS

  The 2024 and 2025 examiners advised evaluating by Java's operator hierarchy, not BODMAS; in 2025 candidates who chose 0 for 42 / 6 % 2 had misapplied precedence.

  ✓Do this: * / % are on one level and go left to right.

  Usually costs: 1 mark.

• ✗Mistake: Confusing prefix and postfix

  The 2024 examiners noted candidates were unclear on pre and post increment.

  ✓Do this: Postfix: use then change; prefix: change then use. Write the value under each operand.

  Usually costs: 1 to 2 marks.

• ✗Mistake: Not handling shorthand assignment

  In 2024 candidates were unclear on shorthand operators in x += ....

  ✓Do this: Expand to x = x + (...), using x's value before the right side changes it.

  Usually costs: 1 mark.

• ✗Mistake: Missing * or Math methods in expressions

  In 2024 candidates missed Math.abs for |a + b|; in 2025 they missed * between terms.

  ✓Do this: Translate every symbol: product = *, |x| = Math.abs, √ = Math.sqrt.

  Usually costs: 1 mark.

Practice questions on Operators in Java

Write each answer on paper first. Open the hint only if you are stuck, and the answer only when you have finished.

1. Q1 · 1 mark · MCQBoard level

   Which is a ternary operator?
   (a) ++
   (b) &&
   (c) ?:
   (d) %

   Hint

   Three operands.

   Answer

   (c) ?:

2. Q2 · 1 mark · MCQHarder board level

   int a = 7; System.out.println(a++ + a);
   (a) 14
   (b) 15
   (c) 16
   (d) 13

   Hint

   Use then change.

   Answer

   (b) 15 (7 + 8)

3. Q3 · 1 mark · MCQBoard level

   Which operator creates memory for an object at run time?
   (a) dot
   (b) new
   (c) =
   (d) ==

   Hint

   Dynamic memory.

   Answer

   (b) new

4. Q4 · 2 marks · Very short answerBoard level

   Distinguish between = and == with an example.

   Hint

   Assign vs compare.

   Answer

   = is the assignment operator that stores a value (a = 5;). == is a relational operator that compares two values and gives true or false (a == 5).

5. Q5 · 2 marks · Short answerHOTS / competency

   int m = 6, n = 9; m *= n % 4 + m--; Find m.

   Hint

   Old m saved.

   Answer

   Saved m = 6. n % 4 = 1; m-- gives 6 (m becomes 5); 1 + 6 = 7; m = 6 × 7 = 42.

6. Q6 · 2 marks · Very short answerHarder board level

   Write the Java expression for (x³ + y³) / (x − y)².

   Hint

   Math.pow.

   Answer

   (Math.pow(x, 3) + Math.pow(y, 3)) / Math.pow(x - y, 2)

7. Q7 · 2 marks · Very short answerHarder board level

   Give the output: int a = 10, b = 3; System.out.println(a / b + " " + a % b + " " + (a > b && b > 5));

   Hint

   Three parts.

   Answer

   3 1 false

8. Q8 · 15 marks · Long answerHarder board level

   Write a program to accept the temperature in Celsius and print it in Fahrenheit (F = 9/5 × C + 32), and print 'Hot' if F is above 100 and 'Not hot' otherwise, using the ternary operator.

   Hint

   Avoid 9/5 integer division.

   Answer

   import java.util.Scanner;
   class Temperature
   {
   public static void main(String args[])
   {
   Scanner sc = new Scanner(System.in);
   System.out.print("Celsius: ");
   double c = sc.nextDouble();
   double f = 9.0 / 5 * c + 32;
   String msg = (f > 100) ? "Hot" : "Not hot";
   System.out.println("Fahrenheit = " + f);
   System.out.println(msg);
   }
   }
   Trace with 40: 9.0 / 5 = 1.8; 1.8 × 40 = 72.0; + 32 = 104.0; output: Fahrenheit = 104.0 / Hot. (Writing 9 / 5 would give 1 and a wrong answer.)

9. Q9 · 2 marks · Short answerHOTS / competency

   Why is 1 / 2 * a * t * t wrong for ½at² in Java?

   Hint

   Integer division.

   Answer

   1 / 2 is integer division giving 0, so the whole product becomes 0. Use 0.5 * a * t * t or 1.0 / 2 * a * t * t.

Test your recall

Answer in your head or on paper first, then open the card. Pulling an answer out of memory makes it stick far better than re-reading.

1. 1.17 % 5 = ?Show answer

   2

2. 2.Which goes first, * or +?Show answer

   *

3. 3.Associativity of assignment?Show answer

   Right to left.

4. 4.What does the dot operator do?Show answer

   Accesses members of a class or object.

5. 5.Initial value of a product accumulator?Show answer

   1

Quick revision checklist

The night before the exam: can you do each of these without looking?

• ☐Unary, binary, ternary.
• ☐Arithmetic, relational, logical, assignment, shorthand, ++/--, ?:.
• ☐Postfix: use then change; prefix: change then use.
• ☐* / % left to right before + −.
• ☐Counter: count++; accumulator: sum += x.
• ☐new allocates memory; dot reaches members.

Operators in Java: frequently asked questions