Module 5.2.2: Parameters in Programming

Parameters

In programming, these are variables that act as placeholders for the input data a function or method needs to operate. Allow functions to accept different values without changing their original code.

Formal Parameters
Actual Parameters

Types of Parameters

Formal Parameters (Placeholder)

These are defined in the function's declaration or definition. They specify the input the function expects.

Actual Parameters (Arguments)

These are the actual values passed when the function is called.

Positional Parameters
Default Parameters
Keyword Parameters
Variable-Length Parameters

Kinds of Parameters

Positional Parameters

Arguments are matched to parameters based on their position in the function call. The order of positional arguments matters.

Default Parameters

Have predefined values that are used when an argument is not supplied.

Keyword Parameter

Keyword arguments are matched by parameter name rather than position.

Variable-Length Parameters

Allow a function to accept different numbers of arguments.

Reusability
Modularity
Modularity
Parameter Passing Mechanisms

Importance of Parameters

Pass by Value
Pass by Reference
Pass by Pointer
Pass by Name

Parameter Passing Mechanisms

Pass by Value

A copy of the argument is passed. Modifying the parameter does not affect the original value.

Pass by Reference

A reference to the argument is passed. Changes to the parameter can affect the original variable.

Pass by Pointer

A pointer to the memory address of the argument is passed. A pointer stores a memory address, allowing the function to access data at that address.

Pass by Name

Expressions are re-evaluated each time they are accessed. A less common parameter-passing mechanism historically associated with languages such as Algol 60. Rather than simply copying a value once, the argument expression can be evaluated in the caller's context whenever the parameter is used.