Computer Science

an electronic component that carries out a logical operation

a table showing the outputs for all possible combinations of inputs to a logic gate or logic circuit

a Boolean operation that outputs True if either, but not both, of the input values are True

Creating an XOR function

Structured programming

Procedures

Functions

Global and local variables

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

Which of the following are built-in operators in Python?

What will this code output?

```one = 4 == 4
two = 2 != 2

print(xor_function(one, two))```

What will this code output?

```one = 4*2  == 32/4
two = 2 == 2

print(xor_function(one, two))```

Which logic gate symbol is used to represent XOR?

What will be the output when this program is run?

```num1 = 5
num2 = 10

if num1 < 6 and num2 > 8:
    print("That is True")
else:
    print("That is False")```

What will be the output when this program is run?

```num1 = 5
num2 = 10

if num1 == 5 or num2 > 11:
    print("That is True")
else:
    print("That is False")```

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

only defined and visible for use in specific parts of a program

What will be the output when this program is run?

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

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

It is difficult to keep track of the value of a global variable.

A variable can be accessed anywhere in the program.

It makes testing harder as you can no longer test a function in isolation.

You can run out of meaningful variable names.

Which of the following are reasons why global variables should be avoided?

{{}} passing is the process of passing data into a subroutine and can be used as an alternative to global variables.

Creating an XOR function

Lesson outcome