135. OCR A Level (H046-H446) SLR23 – 2.2 Global & local variable

What should you have a solid understanding of before watching the videos?

• None of the above

• History of computer science

• Advanced algorithmic strategies

• Basic programming concepts and different data types

Answer explanation

Before watching the videos, you should have a solid understanding of basic programming concepts and different data types.

What is the main purpose of the videos?

• To focus solely on theoretical knowledge

• To teach programming concepts from scratch

• To provide entertainment

• To reinforce and consolidate understanding of programming techniques

Answer explanation

The main purpose of the videos is to reinforce and consolidate understanding of programming techniques.

How does one become a good programmer according to the text?

• By programming little and often

• By only studying theory

• By watching videos exclusively

• By avoiding programming practice

Answer explanation

To become a good programmer, one should program little and often according to the text.

What is the scope of a local variable?

• At the top of a program

• None of the above

• Only within a subroutine

• Throughout the program

Answer explanation

Local variables have scope only within the subroutine where they are declared, not throughout the entire program.

Where is a global variable typically declared?

• Within a specific function only

• At the top of a program

• At the bottom of a program

• Inside a subroutine

Answer explanation

A global variable is typically declared at the top of a program to make it accessible throughout the entire program, not limited to a specific function or subroutine.

What happens to local variables when the subroutine ends?

• They are converted into constants

• They remain active throughout the program

• They are destroyed

• They become global variables

Answer explanation

Local variables are destroyed when the subroutine ends, they do not remain active or become global variables.

Can two variables share the same name if they have different scopes?

• Only if they are constants

• No

• Only in specific programming languages

• Yes

Answer explanation

Yes, two variables can share the same name if they have different scopes in programming.

What is considered poor programming practice?

• Using subroutines

• Declaring variables at the top of a program

• Excessive use of global variables

• Using local variables

Answer explanation

Excessive use of global variables is considered poor programming practice as it can lead to code that is hard to maintain, debug, and test.

What is a safer and better programming practice than using global variables?

• Using only global variables

• Passing in required values to the subroutine by parameters and returning values

• Using constants only

• Avoiding subroutines

Answer explanation

Passing in required values to the subroutine by parameters and returning values is a safer and better programming practice than using global variables because it promotes encapsulation and reduces dependencies.

What does the scope of a variable determine?

• Its value

• Its name

• Where it can be accessed

• Its data type

Answer explanation

The scope of a variable determines where it can be accessed, defining the parts of the code where the variable is visible and can be used.