Tag: programming languages

To solve this question, the user needs to know about short-circuit evaluation in programming languages, particularly in the case of the "&&" operator.

The correct answer is:

The Answer is: A

Explanation:

In programming languages, the "&&" operator represents the logical AND operation. In this operation, if the first expression (exp1) evaluates to false, then the second expression (exp2) is not evaluated because the entire expression is guaranteed to be false. This is known as short-circuit evaluation.

For example, consider the following code:

if (x != null && x.isValid()) {
    // do something
}

In this code, if x is null, then the second expression (x.isValid()) will not be evaluated. This is because the entire expression (x != null && x.isValid()) is guaranteed to be false if x is null. This can improve performance and prevent errors that might occur if the second expression is evaluated when x is null.

Therefore, option A is correct because both the boolean expressions are not always evaluated when the "&&" operator is used.

To solve this question, the user needs to know about Conditional (ternary) Operator.

The conditional operator (also known as the ternary operator) is a shorthand way of expressing a conditional statement. It takes three operands and is denoted as condition ? true_expression : false_expression. The condition is evaluated first, and if it is true, the expression before the colon (:) is evaluated and its value is returned. If the condition is false, the expression after the colon is evaluated and its value is returned.

In the given statement, x is assigned the value of a if a is greater than b, and b otherwise.

Now let's substitute the given values of a and b:

x = (a > b) ? a : b
x = (18 > 27) ? 18 : 27

Since 18 is not greater than 27, the condition a > b is false and x is assigned the value of b, which is 27.

Therefore, the statement "x = (a > b) ? a : b; then the value of x is 27, if a = 18 and b = 27" is true.

The Answer is: A

The statement "Declarations must appear at the start of the body of a Java method" is false.

In Java, variable declarations can appear anywhere within the body of a method, as long as they are declared before they are used. This allows for more flexibility in the design of a program and allows the programmer to declare variables closer to the point of their actual use, making the code more readable and easier to maintain.

Therefore, the correct answer is:

The Answer is: B. False