The solution is trivial when using ^. However, the exam may explicitly forbid using the ^ operator to test understanding of bitwise logic. In that case, we implement XOR via basic bitwise operations:
XOR = (a | b) & ~(a & b)
or equivalently:
XOR = (a & ~b) | (~a & b)
We choose the second form for clarity.
The XOR (exclusive OR) operation yields 1 when bits differ and 0 when they are the same.
Truth table:
| A | B | A XOR B | |---|---|---------| | 0 | 0 | 0 | | 0 | 1 | 1 | | 1 | 0 | 1 | | 1 | 1 | 0 |
In C, the ^ operator performs bitwise XOR. exam 01 piscine 42 exclusive
If you cannot solve an exercise in 5 minutes, skip it. Go back to the previous level and perfect the easier exercise. Because of the linear progression, a 40% score on a Level 3 is worthless compared to a 100% score on a Level 2. Aim for perfect small wins.
Typical exercises: ft_putstr, ft_strlen, ft_swap, ft_strcmp, ft_putchar.
The Trap: People overthink. People use forbidden functions. The Solution: Write from memory. No loops inside loops.
Example: ft_strlen (The perfect answer)
int ft_strlen(char *str) int i;i = 0; while (str[i]) i++; return (i);
Checklist:
You do not write code in a fancy IDE. You are dropped into a shell environment—typically a minimal terminal with vim, emacs, or nano. The grading is done via a proprietary script called Renderium. Here is the exclusive part: You cannot compile your code manually using gcc in the traditional sense. Instead, you submit your .c file to the Renderium system, which compiles it with strict flags (-Wall -Wextra -Werror) and runs a series of hidden tests.
Situation: You have been on ft_split for 30 minutes. It's not working.
Step 1: Punt.
Comment out everything. Write the simplest possible version that returns NULL. Grade it. You get 0%, but you keep your sanity.
Step 2: Simplify.
Ask yourself: "What is the absolute smallest piece of this function that I can get to compile and run?"
Step 3: Trace on paper.
Draw memory. Write your string: "hello world". Walk through your code manually. The solution is trivial when using ^
Step 4: Use printf (during YOUR testing).
The Moulinette doesn't see your prints. Add printf("i=%d\n", i); to debug. Remove before final commit.
Step 5: The "Brute Force" If you can't solve elegantly, solve stupidly. Use a 2D array of fixed size (if allowed). Use nested loops. Get a partial grade. A 50% on Level 3 is better than a 0% because you keep Level 2's grade.
If you are currently swimming (or about to dive) into the infamous 42 Piscine, you have likely heard whispers about a specific event that separates the determined from the lost: Exam 01.
For many candidates, this is the first real psychological and technical wall. The keyword floating around the corridors of 42 campuses worldwide is "exam 01 piscine 42 exclusive" — a phrase that hints at a unique, closed-door challenge that you cannot find on standard coding platforms.
This article provides an exclusive, deep-dive analysis of Exam 01. We will cover its structure, the specific functions you must master, grading secrets, common pitfalls, and the exact mindset required to pass it.