Lecture on Inline Functions in C++

Introduction

• Topic: Use of inline functions with classes in C++.
• Discussion on syntax, pros, and cons of inline functions.

Class Declaration Example: Square

• Class Name: Square
  • Private Member:
    • side (length of the side of the square)
  • Public Functions:
    • Mutator:
      • void setSide(double s) - sets the value of side.
    • Accessors:
      • double getSide() const - returns the value of side.
      • double getArea() const - calculates and returns the area of the square.

Defining Functions

• SetSide Function:
  • Uses void return type.
  • Scope resolution operator (::) is used since function belongs to the square class.
  • Includes input validation to ensure side is positive.
    • If s > 0, update side.
    • Else, terminate the program using exit (requires including <cstdlib>).

Inline Functions

• Key Concept: Functions are declared inline by placing them within the class declaration.
• No inline keyword necessary.
• Example:
  • getSide and getArea defined inline by placing their definitions within the class declaration.

Pros and Cons of Inline Functions

Pros:

• Code Compactness:
  • Functions can be declared in one place, simplifying code structure.
• Performance:
  • Inline expansion by the compiler leads to faster execution as it avoids the function call overhead (e.g., stack usage).

Cons:

• Increased Program Size:
  • Inline code is replicated at each call site, potentially increasing executable size.
• Judgment Call:
  • Decision depends on the trade-off between faster execution and larger file size.

Important Notes

• Do not include the class name and scope resolution operator within the class declaration itself for inline functions.
• Inline functions are ideal for simple functions where call overhead outweighs the space used by code repetition.

Conclusion

• Inline functions offer a balance between performance improvement and code manageability at the cost of potentially larger executables.
• Understanding inline functions enhances efficiency in C++ programming.