Objective

Implement a function that scans the first n bytes of a memory area for a given byte and returns a pointer to the first match, or NULL if it is absent.

Steps

• Look at exactly n bytes starting at s, one at a time, this works on raw memory, not strings, so never stop early on a \0. A matching byte can sit past an embedded NUL as long as it is within the first n bytes.
• Convert c to an unsigned char before comparing: the search byte is the low 8 bits of c, so a value like A + 256 must still match a stored A.
• Return a pointer to the first matching byte. Return NULL when no match is found in the first n bytes, including when n is 0.
• Do not write to the input buffer, and do not call any library function.

Objective

Implement a function that scans the first n bytes of a memory area for a given byte and returns a pointer to the first match, or NULL if it is absent.

Steps

• Look at exactly n bytes starting at s, one at a time, this works on raw memory, not strings, so never stop early on a \0. A matching byte can sit past an embedded NUL as long as it is within the first n bytes.
• Convert c to an unsigned char before comparing: the search byte is the low 8 bits of c, so a value like A + 256 must still match a stored A.
• Return a pointer to the first matching byte. Return NULL when no match is found in the first n bytes, including when n is 0.
• Do not write to the input buffer, and do not call any library function.