Programming Basics LST

What is the primary difference between a variable and a constant in programming?

• A variable can hold multiple data types, while a constant can only hold integers.

• A variable's value can change during program execution, while a constant's value cannot.

• A variable is declared with special characters, while a constant is not.

• A variable is used for loops, while a constant is used for conditions.

Answer explanation

The primary difference is that a variable's value can change during program execution, allowing for dynamic data handling, while a constant's value remains fixed, providing stability in the program.

Which of the following is NOT a valid rule for naming a variable?

• It must start with a letter.

• It can contain spaces.

• It can include numbers.

• It can use underscores.

Answer explanation

Variable names cannot contain spaces, as this would confuse the interpreter. They must start with a letter, can include numbers, and can use underscores, making 'It can contain spaces' the incorrect choice.

In which scenario would you use a constant instead of a variable?

• When the value needs to be updated frequently.

• When the value is used only once in the program.

• When the value is unlikely to change throughout the program.

• When the value is dependent on user input.

Answer explanation

A constant is best used when the value is unlikely to change throughout the program, ensuring stability and clarity. This avoids accidental modifications and enhances code readability.

Which of the following is a correct example of declaring a constant in most programming languages?

• const pi = 3.142

• var pi = 3.142

• let pi = 3.142

• pi = 3.142

Answer explanation

The correct way to declare a constant in most programming languages is using 'const'. Therefore, 'const pi = 3.142' is the right choice, as it indicates that the value of pi cannot be changed after its initial assignment.

What is a potential issue when using global variables in a program?

• They cannot be accessed by any function.

• They can be accidentally modified by local variables with the same name.

• They require more memory than local variables.

• They are automatically deleted after use.

Answer explanation

A potential issue with global variables is that they can be accidentally modified by local variables that share the same name, leading to unexpected behavior in the program.

Why might a programmer choose to use local variables within a function?

• To ensure the variable is accessible throughout the entire program.

• To prevent the variable from being modified outside the function.

• To increase the execution speed of the program.

• To automatically convert the variable to a constant.

Answer explanation

Using local variables within a function prevents them from being modified outside that function, ensuring data integrity and reducing unintended side effects in the program.

Which of the following is NOT a basic programming construct?

• Sequence

• Selection

• Iteration

• Compilation

Answer explanation

Compilation is the process of converting code into machine language, not a basic programming construct. The basic constructs are Sequence, Selection, and Iteration, which define how code is executed.

What does the sequence construct in programming refer to?

• The order in which instructions occur and are processed

• The process of making a decision in a program

• The repeated execution of a section of code

• The declaration of variables

Answer explanation

The sequence construct in programming refers to the order in which instructions occur and are processed. This is fundamental as it determines how the program executes its logic step by step.

What is selection in programming?

• The order in which instructions are executed

• The process of making a decision in a program

• The repeated execution of a section of code

• The declaration of constants

Answer explanation

Selection in programming refers to the process of making a decision in a program, allowing the code to execute different paths based on conditions. This is crucial for controlling the flow of execution.

What is iteration in programming?

• The order in which instructions are executed

• The process of making a decision in a program

• The repeated execution of a section of code

• The declaration of variables

Answer explanation

Iteration in programming refers to the repeated execution of a section of code, allowing for tasks to be performed multiple times until a certain condition is met. This is essential for tasks like looping through data.