Test: Variables and Operators - 2 - Software Development MCQ

JavaScript variables are case-sensitive, meaning "myVariable" and "myvariable" are considered as two different variables.

The "typeof" operator is used to determine the data type of a value stored in a variable.

JavaScript variable names can start with a letter, underscore (_), or a dollar sign ($).

In JavaScript, when the "+" operator is used with a string, it performs concatenation rather than addition.

The "const" keyword is used to declare a constant variable in JavaScript.

The variables x and y are assigned values 10 and 5, respectively. The addition operator (+) adds the values of x and y, resulting in 15.

The variable "name" is assigned the value "John". The string concatenation operator (+) is used to combine the strings "Hello, " and "John", resulting in "Hello, John!".

The variable x is of type number (5) and the variable y is of type string ("10"). When the "+" operator is used between a number and a string, it performs string concatenation.

The "-" operator is used for subtraction in JavaScript. In this case, the string "10" is automatically converted to a number, and the subtraction operation results in 5.

The variable x is initially assigned the value 5. The "+=" operator adds 3 to the current value of x (5 + 3 = 8), and the "*=" operator multiplies the current value of x by 2 (8 * 2 = 16).

The expression "x > y" evaluates to true because 10 is greater than 5. The ternary operator assigns the value "x is greater" to the variable z.

In JavaScript, the "==" operator performs type coercion. In this case, the string "10" is converted to the number 10 before the comparison is made.

The Nullish Coalescing Operator (??) checks if the value of a is null or undefined. Since a is null, it returns the value of b (5).

Comparison operators are used to compare values and return a boolean result, such as true or false.

Logical operators are used to combine or manipulate boolean values and return a boolean result based on the conditions.