When to Use Default Arguments in C++ Functions

Default arguments can be useful in several scenarios:

1. When a function has parameters that have a common default value. This allows callers to omit those arguments if they want to use the default.
2. When you want to extend a function's functionality without breaking existing code. You can add new parameters with default values, and existing callers won't need to change.

For example, consider a function that draws a shape:

1void DrawShape(std::string name, int width,
2  int height, int x = 0, int y = 0) {
3  // Draw the shape...
4}

By providing default values for x and y, we make them optional for the caller. Callers can use the defaults for a simple case:

1// Draws at (0, 0)
2DrawShape("Square", 10, 10);

Or they can provide custom values when needed:

1// Draws at (100, 100)
2DrawShape("Circle", 15, 15, 100, 100);