Computer Science

the section of the program where the variable can be accessed and modified

a variable that is defined and visible for use only in specific parts of a program, e.g. within a subroutine

a variable that is accessible from all parts of a program

Global and local variables

Structured programming

Procedures

Functions

Creating an XOR function

Programming project: subroutines I

Programming project: subroutines 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: subroutines

What value will be output when this program is executed?

```def example():
    number = 10
    print(number)

number = 5
example()```

nothing, because the return value is not held in a variable

What will be the output of this program?

```def multiply(a, b):
    answer = a * b
    return answer

print(multiply(2, 4))```

What will be the output of this program?

```def divide(a, b):
    answer = a / b
    return answer

divide(8, 2)
print(answer)```

What will be the output of this program?

```def add(a, b):
    answer = a + b
    return answer

solution = add(8, 4)
print(solution)```

A procedure executes a list of commands when called. A function will execute a list of commands and also {{}} a value.

What code would correctly call the function `calculate`?

```def calculate(a, b):
    total = a + b
    print(f"{a} + {b} = {total}")
    return total
num1 = 10
num2 = 15```

What are the parameters in this program?

```def calculate(a, b):
    total = a + b
    print(f"{a} + {b} = {total}")
    return total
num1 = 10
num2 = 15
calculate(num1, num2)```

What Python keyword is used to share a value from a function to the rest of the program?

A {{}} can have one, several or no parameters.

What is the definition of values held in the brackets of a subroutine call that are passed into a subroutine via the parameters?

Global and local variables

Lesson outcome