Class 9 Operators in Java Mock Test (ICSE)

Topics in Operators in Java

• Arithmetic, relational and logical operators
• Unary, binary and ternary operators
• Increment and decrement
• Assignment and shorthand operators
• Precedence and associativity
• Writing expressions in Java

Operators in Java practice questions with answers

1. Q1Multiple choice·1 mark
   What will be the result of the following Java expression? `int result = 20 - 4 × 2 / 4 + 6 % 3;`

   1. (a)16
   2. (b)14
   3. (c)20
   4. (d)18
   Show answer and step marks

   1. Correct option: (d) 18. Evaluating multiplication, division and modulus first from left to right: $4 * 2 = 8$, $8 / 4 = 2$, and $6 \% 3 = 0$, followed by subtraction and addition: $20 - 2 + 0 = 18$.+1

   Answer: (d)
2. Q2Multiple choice·1 mark
   After the statements int a = 12; and a *= a - 4; what is the value of a?

   1. (a)8
   2. (b)48
   3. (c)84
   4. (d)96
   Show answer and step marks

   1. Correct option: (d) 96+1

   Answer: (d)
3. Q3Multiple choice·1 mark
   Which operator in Java acts as a shorthand ternary operator taking three operands?

   1. (a)Assignment operator (=)
   2. (b)Conditional operator (? :)
   3. (c)Logical operator (&&)
   4. (d)Relational operator (>)
   Show answer and step marks

   1. Correct option: (b) Conditional operator (? :). The conditional operator `? :` is Java's ternary operator used as a shorthand for if-else constructs.+1

   Answer: (b)
4. Q4Short answer·2 marks
   While planning a snack at home, a student writes the following Java code: int cups = 3; int sugar = 5; boolean ready = cups ≥ 2 || sugar < 4 && cups > 5; Find the value stored in ready and give a reason based on the order in which the operators are evaluated.
   Show answer and step marks

   1. The && operator has higher precedence than ||, so sugar < 4 && cups > 5 is evaluated first: sugar < 4 is false, so the && expression is false.+1
   2. cups ≥ 2 is true, so true || false gives true; hence ready stores true.+1

   Answer: ready stores true, because && is evaluated before || and cups ≥ 2 is true.
5. Q5Long answer·4 marks
   A Java program calculates the bill for an order. The statements below are executed in the given order: int units = 6; int rate = 15; int fee = 4; int extra = (units > 5) ? units - 5 : 0; int credit = -fee; int total = units × rate + fee - extra; (a) Find the value stored in credit after the statement int credit = -fee; is executed. [1] (b) Find the value stored in extra after the statement int extra = (units > 5) ? units - 5 : 0; is executed. [1] (c) Find the value stored in total after the statement int total = units × rate + fee - extra; is executed. [1] (d) State the number of operands taken by the ternary operator ?: in the statement that sets extra. [1]
   Show answer and step marks

   1. (a) Unary minus applied to fee gives credit = -4+1
   2. (b) units > 5 is true (6 > 5), so extra = units - 5 = 1+1
   3. (c) total = 6 × 15 + 4 - 1 = 90 + 4 - 1 = 93+1
   4. (d) ?: takes three operands: the condition, the value if true and the value if false+1

   Answer: (a) -4 (b) 1 (c) 93 (d) 3
6. Q6Long answer·4 marks
   Consider the following code snippet: `int m = 12, n = 5;` `m += n;` `n -= m × 2;` `m *= n + 10;` (a) What are the values of `m` and `n` after the execution of the first two compound-assignment statements (`m += n;` and `n -= m × 2;`)? [2] (b) Calculate the final value of `m` after the complete code snippet is executed. Show the step-by-step working. [2]
   Show answer and step marks

   1. After execution of `m += n;`, `m` becomes $12 + 5 = 17$ and `n` remains $5$.+1
   2. After execution of `n -= m × 2;`, `n` becomes $5 - (17 \times 2) = 5 - 34 = -29$. Therefore, values after two statements are `m = 17`, `n = -29`.+1
   3. For the third statement `m *= n + 10;`, substitute values: $m = 17 \times (-29 + 10) = 17 \times (-19)$.+1
   4. Perform the multiplication: $17 \times -19 = -323$. Final value of `m` is `-323`.+1

   Answer: (a) m = 17, n = -29 (b) m = -323

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