A Level Computer Science OCR Practice Exam

What does the term 'sequence' refer to in programming?

1. A selection of instructions based on user input

2. A series of instructions executed one after another

3. The repetition of a set of instructions

4. A logical decision-making process in coding

The correct answer is: A series of instructions executed one after another

The term 'sequence' in programming refers to a series of instructions executed one after another. This concept is fundamental in programming as it determines the order in which code is run. In a sequence, each instruction is performed in a linear manner, meaning the first instruction is executed, followed by the second, and so on. This straightforward flow of execution is essential for creating programs that operate correctly, given that many algorithms rely on performing tasks in a specific order. For example, consider a simple program that calculates the sum of two numbers. The steps must follow a sequence: first, input the numbers, then add them together, and finally, display the result. If the order of these instructions were altered, the program would not function as intended, highlighting the importance of sequencing in programming structures. The other options point to different programming concepts. The first refers to selection, where different instructions are executed based on conditions, while the third deals with iteration, which involves repeating a set of instructions. The last option relates to decision-making, which is based on evaluating conditions to affect the flow of execution. Understanding sequencing is crucial as it forms the backbone of all programming logic and flow control.