Operators u0026 Expressions Challenge Quiz Quiz

Explore key concepts in programming by answering questions about operators and expressions, including precedence, evaluation order, and usage. Perfect for users looking to sharpen their understanding of arithmetic, logical, and assignment operators across different code scenarios.

1. Operator Precedence in Mixed Expressions

   In the expression 7 + 4 * 2, which value is produced when standard operator precedence rules are applied?

   1. 15
   2. 24
   3. 22
   4. 18

   Explanation: According to standard operator precedence, multiplication is evaluated before addition, so 4 times 2 gives 8, and then 7 plus 8 equals 15. The option 22 results from adding first and then multiplying, which ignores correct precedence. Option 18 and 24 are incorrect as they do not represent any valid evaluation order for this expression.

2. Logical Operator Evaluation

   Given the statement: if (!(true u0026u0026 false) || false), what is the final Boolean value?

   1. null
   2. false
   3. undefined
   4. true

   Explanation: The inner 'true and false' evaluates to false, then its negation gives true. The logical OR with false then yields true. Options null and undefined are not valid Boolean results, and false is incorrect because it ignores how NOT and OR operate here.

3. Compound Assignment Usage

   If variable x equals 8 and we execute x -= 3 * 2, what will be the new value of x?

   1. 2
   2. 3
   3. 12
   4. 10

   Explanation: First, 3 multiplied by 2 equals 6, then x minus 6 is 8 minus 6, which gives 2. The answer 10 incorrectly adds instead of subtracts, 3 results from subtracting 5 rather than 6, and 12 suggests addition when subtraction is required.

4. Short-Circuit Evaluation

   What value will result from evaluating the expression: false || (5 / 0 u003E 1)?

   1. Error
   2. 0
   3. false
   4. true

   Explanation: In many languages, 5 divided by 0 could result in Infinity, and Infinity is greater than 1, so this evaluates to true. Option false incorrectly ignores the right-side expression. 'Error' is not always raised due to short-circuit logic or language support for infinity. Option 0 is irrelevant, as the result must be Boolean.

5. String Concatenation with Operators

   What is the result of the expression: '8' + 4 + 2 in a language where '+' performs string concatenation if either operand is a string?

   1. 842
   2. 8+6
   3. 14
   4. 48

   Explanation: Since '8' is a string, 4 converts to a string and concatenates, resulting in '84', then 2 is concatenated, yielding '842'. Option 14 adds numbers before the string conversion, which is not how concatenation works when a string is first. '48' assumes the operations go right to left. '8+6' interprets the plus as addition rather than string concatenation.