How are Pointers Passed in C : By Value or By Reference?

Pointer Passing in C : Pass by Value or Pass by Reference?

Question:

In C , when passing pointer arguments, does it behave as pass by value or pass by reference?

Answer:

Pointers are passed by value in C , meaning the address of the pointed object is copied into the function parameter. This implies two scenarios:

• Changes to the pointer variable (the address) within the function will not be reflected in the external pointer.
• However, changes made through pointer dereferencing (modifying the pointed object) will be reflected outside the function.

Pointer to Pointer Passing:

If the goal is to change the pointer value itself (point it to a different object), a pointer to pointer is required. This is achieved by using a double ampersand (&&) before the pointer name when passing it to the function. This method is standard practice in C.

References vs. Pointers:

In C , references are preferred over pointers for several reasons:

Advantages of References:

• Reduced syntaxic noise in function bodies
• More information provided to the compiler, allowing for optimizations

Drawbacks of References:

• Break the pass-by-value rule of C, requiring more attention to parameter behavior
• Not supported in C

Specific Case: Pointer to Pointer vs. Reference

In the case of pointer to pointer passing, the main difference with using a reference is simplicity. By passing a reference to the outer pointer, both levels of indirection can be eliminated, providing a more straightforward approach.

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