NULL vs. 0 in C : Which Should I Use for Null Pointers?

The Dilemma of Null Pointers: NULL vs. 0

In the tapestry of C coding practices, a debate has emerged regarding the usage of NULL versus 0 (zero) for null pointers. The origins of this discussion lie in the early days of C , when NULL was defined as (void*)0. This constraint limited its assignment to void pointers, rendering it somewhat impractical. Consequently, developers adopted the convention of using 0 as a null pointer.

Preferences have persisted despite the evolution of C . Some programmers, like the author, favor 0 due to its intuitive use as a null value and its compatibility with truth value testing (if (p && !q)). Conversely, others advocate for NULL based on aesthetics.

To address this ongoing question, let's consider the perspective of Bjarne Stroustrup, the creator of C . According to Stroustrup's C Style and Technique FAQ, NULL is effectively synonymous with 0 in C , making it a matter of personal preference. He suggests using 0 to avoid macros and emphasizes that pre-standard NULL definitions sometimes led to unexpected behavior.

In C 11, the nullptr keyword was introduced to explicitly define the null pointer value. However, Stroustrup recommends focusing on code functionality rather than dwelling on nuances.

Ultimately, the choice between NULL and 0 remains a matter of personal preference. Both approaches have their merits, and neither is inherently superior. It's important to ensure consistency within a coding team or project, but there is no objective reason to definitively prefer one option over the other.

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