Functions are fundamental components in programming that allow you to group related instructions together, make your code more modular, and promote reusability. In pseudocode, functions are used to structure algorithms and simplify complex tasks by breaking them down into smaller, more manageable pieces.

Function Syntax

The basic syntax for defining a function in pseudocode is:

FUNCTION function_name (parameters)
statements
RETURN value
END FUNCTION

Here, "function_name" is the name of the function, "parameters" are the inputs that the function takes, "statements" are the actions the function performs, and "value" is what the function returns.

Example of a Simple Function

FUNCTION calculate_sum (a, b)
sum = a + b
RETURN sum
END FUNCTION
INPUT x, y
result = calculate_sum(x, y)
OUTPUT result

This function takes two parameters, adds them together, and returns the sum. For more information on input and output operations, check the Input/Output in Pseudocode guide.

Functions with Multiple Return Values

Some functions may need to return multiple values. In pseudocode, we can represent this as follows:

FUNCTION calculate_stats (numbers)
sum = 0
count = 0
FOR EACH num IN numbers
sum = sum + num
count = count + 1
END FOR
average = sum / count
RETURN sum, count, average
END FUNCTION
data = [1, 2, 3, 4, 5]
total, quantity, mean = calculate_stats(data)
OUTPUT "Sum:", total, "Count:", quantity, "Average:", mean

Recursive Functions

Functions can call themselves, which is known as recursion. Here's an example of a recursive function to calculate factorial:

FUNCTION factorial (n)
IF n = 0 OR n = 1 THEN
RETURN 1
ELSE
RETURN n * factorial(n - 1)
END IF
END FUNCTION
INPUT num
result = factorial(num)
OUTPUT "Factorial of", num, "is", result

Remember, the goal of pseudocode is to communicate logic clearly. While the exact syntax may vary, the important thing is to convey the structure and purpose of your functions in a way that's easy to understand and translate into actual code.