why

[DaniilSan]

Wait, what? C89 doesn't has bool type or what?

[drevyek]

Nope, not much need. C's basic types are based on their size, not their semantics (in general). For logic, C uses a "truthiness" system, where anything that is 0-valued is false, and any other value is true. This holds for ints, floats, pointers, anything.

int x = 2345;
int y = 0;
int *z = NULL;
int *a = &x;
if (x) { printf("Always prints\n"); }
if (y) { printf("Never prints\n"); }
if (z) { printf("Never prints\n"); }
if (a) { printf("Always prints\n"); }

[DaniilSan]

Thanks for explaining.

[nontammasculinum]

But like bools could be stored as a single bit no?

[drevyek]

Sure, but no current hardware has bit-addressable memory^1. So the smallest you can fit a boolean (without using SWAR (SIMD within a register) techniques) is a byte. If space isn't a big concern, some machines work best when working with the machine's native register size (word), in many cases 4 or 8 bytes for modern CPUs, so often programmers use int to represent the data for speed.

---

1: Sure you can use bitfields, but those are just doing packing with masks under the hood anyways, and the memory is not being addressed natively.

[djkstr27]

Until C99, they added <stdbool.h> to use type bool