strrchr

Strings: walking and searching16

Objective

Implement a function that scans a string for the last occurrence of a character and returns a pointer to it.

Steps

Walk the whole string, comparing each character against c (which arrives as an int but is matched as a char).
Remember the most recent match instead of returning on the first one: the result must point at the *last* occurrence.
If the character never appears, return NULL.
The terminating '\0' counts as part of the string: searching for '\0' must return a pointer to the terminator, not NULL. Make sure your scan still inspects that final byte.
Do not modify the input buffer.

examples

$ strrchr("merge merge", 'e')

$ strrchr("git status", 'z')

(null)

$ strrchr("commit", '\0')

(no output)

Constraints

Expected files

strrchr.c

Allowed functions

None. Write every helper yourself.

Allowed headers

<stddef.h>defines NULL

libc

Standard C library

Implements the contract of a function from the standard C library.

Tests

Run the tests to grade your code

Build

01Returns the last of several matches

02Single match at the first character

03Last match falls in the second word

04Single occurrence

05Character absent

06Searching for the terminator

07Empty string, character absent

08Empty string, searching for the terminator

strrchr

Objective

Implement a function that scans a string for the last occurrence of a character and returns a pointer to it.

Steps

Walk the whole string, comparing each character against c (which arrives as an int but is matched as a char).
Remember the most recent match instead of returning on the first one: the result must point at the *last* occurrence.
If the character never appears, return NULL.
The terminating '\0' counts as part of the string: searching for '\0' must return a pointer to the terminator, not NULL. Make sure your scan still inspects that final byte.
Do not modify the input buffer.

examples

$ strrchr("merge merge", 'e')

$ strrchr("git status", 'z')

(null)

$ strrchr("commit", '\0')

(no output)

Constraints

Expected files

strrchr.c

Allowed functions

None. Write every helper yourself.

Allowed headers

<stddef.h>defines NULL

libc

Standard C library

Implements the contract of a function from the standard C library.

strrchr

Strings: walking and searching16

Objective

Implement a function that scans a string for the last occurrence of a character and returns a pointer to it.

Steps

Walk the whole string, comparing each character against c (which arrives as an int but is matched as a char).
Remember the most recent match instead of returning on the first one: the result must point at the *last* occurrence.
If the character never appears, return NULL.
The terminating '\0' counts as part of the string: searching for '\0' must return a pointer to the terminator, not NULL. Make sure your scan still inspects that final byte.
Do not modify the input buffer.

examples

$ strrchr("merge merge", 'e')

$ strrchr("git status", 'z')

(null)

$ strrchr("commit", '\0')

(no output)

Constraints

Expected files

strrchr.c

Allowed functions

None. Write every helper yourself.

Allowed headers

<stddef.h>defines NULL

libc

Standard C library

Implements the contract of a function from the standard C library.

Tests

Run the tests to grade your code

Build

01Returns the last of several matches

02Single match at the first character

03Last match falls in the second word

04Single occurrence

05Character absent

06Searching for the terminator

07Empty string, character absent

08Empty string, searching for the terminator