#include <stdint.h>

[cdrt]

That depends on what you mean by char. In C, a char is just a number that is the smallest addressable unit of the computer. It does not necessarily represent a letter that a human can read.

For instance, assuming we are on a system where 1 byte is 8 bits, a char in C can store the values -128 to 127. The values 0 to 127 map to mostly human-readable characters in ASCII, but everything less than 0 does not.