Computer Science

a sequence of instructions to perform a specific task with an identifiable name

describes how a subprogram will interact with the main program

used in a subprogram to allow values to be passed into them

Structured programs

Procedures in programs

Functions in programs

Global and local variables in programs

Programming project: subprograms I

Programming project: subprograms II

In this unit pupils will be introduced to structured programming. They will explore the differences between functions and procedures and use functions to return values in programs. They will be introduced to the concept of scope and how parameters can be used to reduce the need for global variables.

Programming: subprograms

Subprograms make use of return values so the use of global variables is reduced.

A structured program will execute more quickly.

Subprograms are easier to test because they perform a single task.

Meaningful identifiers for subprograms help to make the program code readable.

It is quicker because many subprograms can be worked on at the same time.

The structured approach to programming provides many benefits.

From the list below select the statements that specify a benefit of using the structured approach.

A subprogram must be defined and executed at some point in the program.

Subprograms make programs easier to read and understand.

Procedures allow values to be returned to the procedure call.

A student wants a subprogram that will add any two given numbers together and to display the answer. Use the lines of code below to construct a display_sum subprogram for them.

What is num1 in this line of code?
 ```def display_sum (num1, num2):```

Programming languages are considered to be high or low level, which of the following languages are high level?

What Python function is used to display output?

What operator is used for multiplication in Python?

Can you work out the value of the variable total once the code has finished executing?

```total = 0
FOR i = 0 TO 3
    FOR j = 0 TO i
        total = total + i
    NEXT j
NEXT i```

What data type is used in Python to hold whole numbers?

Which type of loop is used for condition controlled iteration in Python?

Structured programs

Lesson outcome