Defined in header <stdlib.h>

Defined in header <math.h>

Usage boolean type: as the declaration of the type

Comparison operators are binary operators that test a condition and return 1 if that condition is logically true and 0 if that condition is false

Usage _Alignof

Defined in header <wchar.h>

Defined in header <string.h>

Defined in header <stdio.h>

Defined in header <stdlib.h>

Defined in header <ctype.h>