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The problem

A configuration loader reads numbers typed by users, such as " -042", "1337px" and "99999999999", and must turn them into 32-bit integers the way C's atoi does: skip leading spaces, read one optional sign, read digits until the first non-digit, and clamp anything outside the 32-bit range. The interviewer wants it written recursively: each call handles one character and passes the value built so far to the next call, so the "loop" becomes the call chain.

Example: " -042" → -42; "-91283472332" → -2147483648.

Function signature

int myAtoi(const string& s);

Test cases

Input	Output	Explanation
"42"	42
" -042"	-42	Spaces, a sign and leading zeros
"1337c0d3"	1337	Stops at the first non-digit
"words and 987"	0	No digits before the first letter
"-91283472332"	-2147483648	Clamped to INT_MIN
"+-12"	0	Only one sign is allowed

(Confirm: only the space character counts as whitespace; no digits means 0; results are clamped to [−2³¹, 2³¹ − 1].)

How interviewers phrase it

• "Implement myAtoi(string s), which converts a string to a 32-bit signed integer" (LeetCode 8), with the extra requirement "do it recursively".

Clarifying questions to ask

1. Which characters count as whitespace? (Only ' ' in LeetCode's version.)
2. What happens on overflow? (Clamp to INT_MIN or INT_MAX.)
3. What if there are no digits? (Return 0.)

Follow-ups to expect

1. "What does each recursive call do?"
2. "How do you detect overflow without overflowing?"
3. "Why keep the sign separately?"
4. "What's the recursion depth?"
5. "Iterative vs recursive?"

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