v0.40: Create exercises. Challenge the community.

strrchr

Your mission

Implement gm_strrchr, your own strrchr, which scans a string for the last occurrence of a character and returns a pointer to it.

See it in action

gm_strrchr("merge merge", 'e')

Expected result

Your checklist

For your own tracking. Tests grade your code.

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.

More examples

gm_strrchr("git status", 'z')

Expected result

(null)

gm_strrchr("commit", '\0')

Expected result

(empty result)

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 searching

Your mission

Implement gm_strrchr, your own strrchr, which scans a string for the last occurrence of a character and returns a pointer to it.

See it in action

gm_strrchr("merge merge", 'e')

Expected result

Your checklist

For your own tracking. Tests grade your code.

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.

More examples

gm_strrchr("git status", 'z')

Expected result

(null)

gm_strrchr("commit", '\0')

Expected result

(empty result)

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 your code, then check each test here. Open a result to inspect its output.

Build

01Returns the last of several matchesWaiting

02Single match at the first characterWaiting

03Last match falls in the second wordWaiting

04Single occurrenceWaiting

05Character absentWaiting

06Searching for the terminatorWaiting

07Empty string, character absentWaiting

08Empty string, searching for the terminatorWaiting

strrchr

Your mission

Implement gm_strrchr, your own strrchr, which scans a string for the last occurrence of a character and returns a pointer to it.

See it in action

gm_strrchr("merge merge", 'e')

Expected result

Your checklist

For your own tracking. Tests grade your code.

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.

More examples

gm_strrchr("git status", 'z')

Expected result

(null)

gm_strrchr("commit", '\0')

Expected result

(empty result)

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.

v0.40: Create exercises. Challenge the community.

Meet Studio →

strrchr

Strings: walking and searching

Your mission

Implement gm_strrchr, your own strrchr, which scans a string for the last occurrence of a character and returns a pointer to it.

See it in action

gm_strrchr("merge merge", 'e')

Expected result

Your checklist

For your own tracking. Tests grade your code.

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.

More examples

gm_strrchr("git status", 'z')

Expected result

(null)

gm_strrchr("commit", '\0')

Expected result

(empty result)

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 your code, then check each test here. Open a result to inspect its output.

Build

01Returns the last of several matchesWaiting

02Single match at the first characterWaiting

03Last match falls in the second wordWaiting

04Single occurrenceWaiting

05Character absentWaiting

06Searching for the terminatorWaiting

07Empty string, character absentWaiting

08Empty string, searching for the terminatorWaiting