Objective

Write a function that returns a pointer to the first int equal to value inside the half-open range [first, last), and last itself when the value never shows up.

Steps

• first points at the first int to inspect. last points one past the last one, so you may compare against it but never read through it.
• Scan upward from first and return the address of the first element equal to value.
• When no element matches, return last. Not NULL.
• An empty range (first == last) matches nothing: return last without reading a single int.
• If value appears several times, return the earliest occurrence.
• Only the elements inside the range count. A match sitting just before first or at last is out of scope.
• value can be 0, negative, INT_MIN or INT_MAX. No value is treated as special.
• This convention differs from the memchr exercise on purpose: memchr walks raw bytes and returns NULL when it finds nothing, while a half-open range returns its end pointer. Both are standard C practice.
• Do not modify the range, and do not call any library function.
• The tests print ret - first, the offset of your answer. An absent value therefore prints the length of the range.

Objective

Write a function that returns a pointer to the first int equal to value inside the half-open range [first, last), and last itself when the value never shows up.

Steps

• first points at the first int to inspect. last points one past the last one, so you may compare against it but never read through it.
• Scan upward from first and return the address of the first element equal to value.
• When no element matches, return last. Not NULL.
• An empty range (first == last) matches nothing: return last without reading a single int.
• If value appears several times, return the earliest occurrence.
• Only the elements inside the range count. A match sitting just before first or at last is out of scope.
• value can be 0, negative, INT_MIN or INT_MAX. No value is treated as special.
• This convention differs from the memchr exercise on purpose: memchr walks raw bytes and returns NULL when it finds nothing, while a half-open range returns its end pointer. Both are standard C practice.
• Do not modify the range, and do not call any library function.
• The tests print ret - first, the offset of your answer. An absent value therefore prints the length of the range.