v0.40: Create exercises. Challenge the community.

strchr

Your mission

Implement gm_strchr, your own strchr, which scans a string for the first occurrence of a character and returns a pointer to it.

See it in action

gm_strchr("rebase main", 'm')

Expected result

main

Your checklist

For your own tracking. Tests grade your code.

Walk through the string character by character, comparing each one against c (which arrives as an int but is matched as a char).
On the first match, return a pointer to that character inside the string.
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.
Do not modify the input buffer.

More examples

gm_strchr("git status", 'z')

Expected result

(null)

gm_strchr("commit", '\0')

Expected result

(empty result)

Constraints

Expected files

strchr.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.

strchr

Strings: walking and searching

Your mission

Implement gm_strchr, your own strchr, which scans a string for the first occurrence of a character and returns a pointer to it.

See it in action

gm_strchr("rebase main", 'm')

Expected result

main

Your checklist

For your own tracking. Tests grade your code.

Walk through the string character by character, comparing each one against c (which arrives as an int but is matched as a char).
On the first match, return a pointer to that character inside the string.
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.
Do not modify the input buffer.

More examples

gm_strchr("git status", 'z')

Expected result

(null)

gm_strchr("commit", '\0')

Expected result

(empty result)

Constraints

Expected files

strchr.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

01Character in the middleWaiting

02Character is the first characterWaiting

03Returns the first of several matchesWaiting

04Character is the last characterWaiting

05Character absentWaiting

06Searching for the terminatorWaiting

07Empty string, character absentWaiting

08Empty string, searching for the terminatorWaiting

strchr

Your mission

Implement gm_strchr, your own strchr, which scans a string for the first occurrence of a character and returns a pointer to it.

See it in action

gm_strchr("rebase main", 'm')

Expected result

main

Your checklist

For your own tracking. Tests grade your code.

Walk through the string character by character, comparing each one against c (which arrives as an int but is matched as a char).
On the first match, return a pointer to that character inside the string.
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.
Do not modify the input buffer.

More examples

gm_strchr("git status", 'z')

Expected result

(null)

gm_strchr("commit", '\0')

Expected result

(empty result)

Constraints

Expected files

strchr.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.

strchr

Strings: walking and searching

Your mission

Implement gm_strchr, your own strchr, which scans a string for the first occurrence of a character and returns a pointer to it.

See it in action

gm_strchr("rebase main", 'm')

Expected result

main

Your checklist

For your own tracking. Tests grade your code.

Walk through the string character by character, comparing each one against c (which arrives as an int but is matched as a char).
On the first match, return a pointer to that character inside the string.
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.
Do not modify the input buffer.

More examples

gm_strchr("git status", 'z')

Expected result

(null)

gm_strchr("commit", '\0')

Expected result

(empty result)

Constraints

Expected files

strchr.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

01Character in the middleWaiting

02Character is the first characterWaiting

03Returns the first of several matchesWaiting

04Character is the last characterWaiting

05Character absentWaiting

06Searching for the terminatorWaiting

07Empty string, character absentWaiting

08Empty string, searching for the terminatorWaiting

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