The most exclusive part of the 42 experience is the immediate feedback. When you submit, you wait. The "Grade: 0" notification is a rite of passage.
unsigned char ft_exclusive(unsigned char a, unsigned char b)
write(1, &str[i], 1); i++;
Your grade = The level of the last exercise you solved perfectly.
One feature that makes Exam 01 truly unique to 42 is the (the automated grading system) is compiled with fsanitize=address for memory leaks. In most coding exams, if your program leaks memory but returns the correct value, you might pass. Not here.