Computing
Computer Science LearnITWithMrC ⛯ Year 7 Year 8 Year 9 GCSE

## Lesson Video 10

• Watch the Lesson video
Make notes on your notes sheet.
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• Complete the learning activities
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• Check the Learning outcomes

## What do I need to Learn?

 I need to learn how to understand that the three combining principles (sequence, iteration/repetition and selection/choice) are basic to all imperative programming languages.

## Key Terms

Imperative languages Declarative languages Sequences Iteration Selection Assignment Comparison operations

## Imperative languages

Imperative languages are a style of language that are built from commands which state how the program must operate. A command is an instruction that the computer must follow.

### Three Principles of Imperative Languages

The three key elements of imperative programming languages are:

1. Sequence - The order in which commands are executed
2. Selection - The ability to branch the code depending upon a condition.
3. Iteration The ability to repeat the code based upon a condition.

The key features of imperative programming languages are:

• Variables - A label with an assigned values thats is created to store the value of a data type in memory. A variable can change its value while the program is running.
• Constants - Constants are identical to variables, except that the value cannot be changed while the program is running
• Assignment Placing a value into a variable.
• Mathematical operations The ability to compute calculations using operators such as + - = etc.
• Comparison operations Operators Used to compare values and create true or false results such as > < == etc.
• Subroutines A piece of code that is defined by its own name and that can be reused by reference to that name. It can return a value and be passed values.
• Flowchart examples for the three key elements:
Sequence,Selection and Iteration (repetition)