Function

Modular Design

A design method that divides a system into smaller parts (modules) which can be independently created and then fit together. Some general guidelines for defining a module include:

• The module is easy to upgrade.
• The module contains a readable amount of code.
• The module may be used as part of the solution to some other problem.
• For a structured design, we stipulate that each module has one entry point and one exit point, each module is highly cohesive, and each module exhibits low coupling.

Cohesion

It refers to how closely all the routines in a module support a central purpose. High cohesion means each module has a single, well-defined task.

Coupling

It refers to the interdependence between modules. Loose coupling means each module is independent as much as possible.

A better design is one that has high cohesion (each module does one thing well) and loose coupling (each module is independent).

Functions

Definition

A function in C is a block of code that performs a specific task. It is the building block of modular programming.

Basic Syntax

• Function Definition: It includes the function's name, return type and parameters.

// function declaration
return_type function_name(parameter1, parameter2, ...){
    // code
    return value;
}

• Function Call: It includes the function's name and arguments.

// function call
function_name(argument1, argument2, ...);

Pass by Value

In C, arguments are passed to functions by value. It means that a copy of the data is made and used inside the function, not affecting the original data.

Type Mismatch in Arguments and Parameters

If the type of an argument does not match the type of the corresponding parameter in the function definition, the C compiler will try to convert the argument to the type of the parameter. If this is not possible, an error will occur.