Hexadecimal numbers use base 16.
The characters used in hexadecimal numbers are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, and F.
You can print numbers in hexadecimal form by using the format "x".
#include
main()
{
int i = 65;
printf("%x", i);
}