Describe the structured approach to programming.

The idea

Structured programming means breaking a program into small, self-contained modules — subroutines such as procedures and functions — each with one clear job, rather than writing one long sequence of instructions. A procedure performs a task and may return no value; a function performs a task and returns a value. Modules are called from a main routine, receive data through parameters and pass results back. Each module can be written, tested and corrected on its own, and reused elsewhere. For example, a program that calculates wages might use a function to compute pay from hours and rate, and a procedure to print a payslip. Structured code uses sequence, selection and iteration within each module and avoids unstructured jumps.

What earns the marks

• Structured programming splits a program into separate modules or subroutines, each responsible for one well-defined task.
• Subroutines include procedures (carry out a task, return no value) and functions (carry out a task and return a value).
• Modules communicate by being called, passing data in through parameters and returning results.
• Each module can be developed, tested and debugged independently, and reused in other programs.
• Within modules, control uses sequence, selection and iteration rather than unstructured jumps.
• A main routine calls the modules in the required order to form the whole program.

Common mistakes and how to put them right

• Thinking structured programming means only using indentation or comments.

  Put it right: It is about decomposing the program into modules with defined tasks.

• Confusing procedures and functions.

  Put it right: A function returns a value while a procedure does not.

• Believing a subroutine must be written before the main program runs in a fixed order.

  Put it right: Modules are defined and then called when needed.

• Assuming structured programming forbids selection or loops.

  Put it right: These constructs are used inside modules.

Exam tips

• Learn a one-line definition of a module and be ready to identify procedures versus functions in a short code extract.
• When given a scenario, name the separate tasks that could each become a subroutine.
• Check whether an option describes decomposition, parameters or return values before choosing it.