memset

Your mission

Implement gm_memset, your own memset, which fills the first n bytes of a memory area with a single byte value, then returns the area's address.

See it in action

gm_memset(buf, 'A', 5)  // then buf[5]='\0'; print buf

Expected result

AAAAA

Your checklist

For your own tracking. Tests grade your code.

Walk the memory area s byte by byte and write the same byte into each of the first n positions.
The byte to write comes from c: convert it to unsigned char before storing, so only the low 8 bits are used.
Write exactly n bytes, no more, no less. When n is 0, touch nothing at all.
Return the original pointer s (the address you were given), not a cursor that walked to the end.

More examples

gm_memset("commit", '0', 3)  // first 3 bytes only

Expected result

000mit

Constraints

Expected files

memset.c

Allowed functions

None. Write every helper yourself.

Allowed headers

<stddef.h>defines size_t

libc

Standard C library

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

memset

Bytes and raw memory

Your mission

Implement gm_memset, your own memset, which fills the first n bytes of a memory area with a single byte value, then returns the area's address.

See it in action

gm_memset(buf, 'A', 5)  // then buf[5]='\0'; print buf

Expected result

AAAAA

Your checklist

For your own tracking. Tests grade your code.

Walk the memory area s byte by byte and write the same byte into each of the first n positions.
The byte to write comes from c: convert it to unsigned char before storing, so only the low 8 bits are used.
Write exactly n bytes, no more, no less. When n is 0, touch nothing at all.
Return the original pointer s (the address you were given), not a cursor that walked to the end.

More examples

gm_memset("commit", '0', 3)  // first 3 bytes only

Expected result

000mit

Constraints

Expected files

memset.c

Allowed functions

None. Write every helper yourself.

Allowed headers

<stddef.h>defines size_t

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

01Fill 5 bytes, print as stringWaiting

02Fill only the first 3 bytesWaiting

03Zero length leaves the buffer untouchedWaiting

04c is truncated to one byte (0x141 -> 'A')Waiting

05Fill with NUL bytesWaiting

06Returns the original pointerWaiting

memset

Your mission

Implement gm_memset, your own memset, which fills the first n bytes of a memory area with a single byte value, then returns the area's address.

See it in action

gm_memset(buf, 'A', 5)  // then buf[5]='\0'; print buf

Expected result

AAAAA

Your checklist

For your own tracking. Tests grade your code.

Walk the memory area s byte by byte and write the same byte into each of the first n positions.
The byte to write comes from c: convert it to unsigned char before storing, so only the low 8 bits are used.
Write exactly n bytes, no more, no less. When n is 0, touch nothing at all.
Return the original pointer s (the address you were given), not a cursor that walked to the end.

More examples

gm_memset("commit", '0', 3)  // first 3 bytes only

Expected result

000mit

Constraints

Expected files

memset.c

Allowed functions

None. Write every helper yourself.

Allowed headers

<stddef.h>defines size_t

libc

Standard C library

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

memset

Bytes and raw memory

Your mission

Implement gm_memset, your own memset, which fills the first n bytes of a memory area with a single byte value, then returns the area's address.

See it in action

gm_memset(buf, 'A', 5)  // then buf[5]='\0'; print buf

Expected result

AAAAA

Your checklist

For your own tracking. Tests grade your code.

Walk the memory area s byte by byte and write the same byte into each of the first n positions.
The byte to write comes from c: convert it to unsigned char before storing, so only the low 8 bits are used.
Write exactly n bytes, no more, no less. When n is 0, touch nothing at all.
Return the original pointer s (the address you were given), not a cursor that walked to the end.

More examples

gm_memset("commit", '0', 3)  // first 3 bytes only

Expected result

000mit

Constraints

Expected files

memset.c

Allowed functions

None. Write every helper yourself.

Allowed headers

<stddef.h>defines size_t

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

01Fill 5 bytes, print as stringWaiting

02Fill only the first 3 bytesWaiting

03Zero length leaves the buffer untouchedWaiting

04c is truncated to one byte (0x141 -> 'A')Waiting

05Fill with NUL bytesWaiting

06Returns the original pointerWaiting