Function Calling

Call by Value:

Call by Value is a parameter passing mechanism in programming where a copy of the actual data is passed to a function or method. In this approach, any modifications made to the parameter within the function do not affect the original data outside the function.


Key Characteristics:

  • Copy of Data: When a function is called with parameters passed by value, a duplicate of the data is created inside the function's scope.
  • No Impact on Original: Any changes made to the parameter within the function are limited to the local copy and do not alter the original data.
  • Isolation: Call by Value ensures data isolation, making it suitable for situations where you want to preserve the integrity of the original data.

Use Cases:

  • Immutable Data: Call by Value is often used with immutable data types or objects where you don't want the original data to be modified.
  • Predictable Behavior: It provides predictable behavior, making it useful for functions that should not have side effects on the calling code.
  • Simplicity: In scenarios where simplicity and data preservation are important, Call by Value is a suitable choice.

Call by Reference:

Call by Reference is another parameter passing mechanism where a reference or memory address of the actual data is passed to a function. In this approach, any changes made to the parameter within the function directly affect the original data outside the function.


Key Characteristics:

  • Reference to Data: Call by Reference passes a reference or pointer to the original data, allowing direct manipulation.
  • Changes Affect Original: Modifications made to the parameter within the function impact the original data, making it suitable for scenarios where you want to alter the original data.
  • Efficiency: Call by Reference can be more efficient since it avoids copying data, especially for large objects.

Use Cases:

  • In-Place Modifications: Call by Reference is commonly used when you need to perform in-place modifications on data structures.
  • Efficiency Matters: It's beneficial in situations where efficiency and avoiding data duplication are critical.
  • Shared State: In scenarios where multiple functions or components need to work with and modify the same data, Call by Reference is a practical choice.