Maintaining Programs

Exam code: 2210

Written by: Ashika|Reviewed by: Caroline Carroll|Updated 2 July 2026

Maintaining Programs

How do you write programs that are easy to maintain?

Easy to maintain programs are written using techniques that make code easy to read
Programmers should be consistent with the use of techniques such as:
- Layout - spacing between sections
- Indentation - clearly defined sections of code
- Comments - explaining key parts of the code
- Meaningful variable names - describe what is being stored
- White space - adding suitable spaces to make it easy to read
- Sub-programs - Functions or procedures used where possible
When consistency is applied, programs are easy to maintain

Example easy to-maintain program

Python code
Calculates the area of a triangle given its base and height Inputs: base (float): The length of the triangle's base (positive value) height (float): The height of the triangle from the base (positive value) Returns: The calculated area of the triangle (float) Raises: ValueError: If either base or height is non-positive
def calculate_area_of_triangle(base, height): if base <= 0 or height <= 0: raise ValueError("Base and height must be positive values.") area = 0.5 * base * height # Corrected multiplication syntax return area def main(): # ----------------------------------------------------------------------- # Prompts the user for triangle base and height, calculates and prints the area # ----------------------------------------------------------------------- try: base = float(input("Enter the base of the triangle: ")) height = float(input("Enter the height of the triangle: ")) # Call the area calculation function area = calculate_area_of_triangle(base, height) print(f"The area of the triangle is approximately {area:.2f} square units.") except ValueError as error: print(f"Error: {error}") # ------------------------------------------------------------------------ # Main program # ------------------------------------------------------------------------ main()

Python code

Calculates the area of a triangle given its base and height

Inputs:

base (float): The length of the triangle's base (positive value)

height (float): The height of the triangle from the base (positive value)

Returns:

The calculated area of the triangle (float)

Raises:

ValueError: If either base or height is non-positive

def calculate_area_of_triangle(base, height):
    if base <= 0 or height <= 0:
        raise ValueError("Base and height must be positive values.")

    area = 0.5 * base * height  # Corrected multiplication syntax
    return area

def main():
    # -----------------------------------------------------------------------
    # Prompts the user for triangle base and height, calculates and prints the area
    # -----------------------------------------------------------------------
    try:
        base = float(input("Enter the base of the triangle: "))
        height = float(input("Enter the height of the triangle: "))

        # Call the area calculation function
        area = calculate_area_of_triangle(base, height)

        print(f"The area of the triangle is approximately {area:.2f} square units.")

    except ValueError as error:
        print(f"Error: {error}")

# ------------------------------------------------------------------------
# Main program
# ------------------------------------------------------------------------

main()

Maintaining Programs

Maintaining Programs

How do you write programs that are easy to maintain?

Example easy to-maintain program

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