v0.40: Create exercises. Challenge the community.

macro_flags

Your mission

Implement four bit flag macros in flags.h, then use them in update_flag.

See it in action

SET_FLAG(4u, 0)

Expected result

Your checklist

For your own tracking. Tests grade your code.

Write flags.h and flags.c.
FLAG(bit) returns an unsigned value with only bit set.
HAS_FLAG(value, bit) is true when that bit is set in value.
SET_FLAG(value, bit) returns value with that bit set.
CLEAR_FLAG(value, bit) returns value with that bit cleared.
Parenthesise every macro parameter and the complete expansion. Grademe passes expressions, not only variable names.
update_flag sets the selected bit when enabled is nonzero and clears it when enabled is zero.
The valid bit range is 0 through 31.

More examples

CLEAR_FLAG(7u, 1)

Expected result

Constraints

Expected files

flags.hflags.c

Allowed functions

None. Write every helper yourself.

macro_flags

Headers and the preprocessor

Your mission

Implement four bit flag macros in flags.h, then use them in update_flag.

See it in action

SET_FLAG(4u, 0)

Expected result

Your checklist

For your own tracking. Tests grade your code.

Write flags.h and flags.c.
FLAG(bit) returns an unsigned value with only bit set.
HAS_FLAG(value, bit) is true when that bit is set in value.
SET_FLAG(value, bit) returns value with that bit set.
CLEAR_FLAG(value, bit) returns value with that bit cleared.
Parenthesise every macro parameter and the complete expansion. Grademe passes expressions, not only variable names.
update_flag sets the selected bit when enabled is nonzero and clears it when enabled is zero.
The valid bit range is 0 through 31.

More examples

CLEAR_FLAG(7u, 1)

Expected result

Constraints

Expected files

flags.hflags.c

Allowed functions

None. Write every helper yourself.

Tests

Run the tests to grade your code

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

Build

01Builds one bit at either end of the rangeWaiting

02Tests the selected bitWaiting

03Sets and clears without touching neighboursWaiting

04Expressions keep their intended precedenceWaiting

05The source file uses the header contractWaiting

macro_flags

Your mission

Implement four bit flag macros in flags.h, then use them in update_flag.

See it in action

SET_FLAG(4u, 0)

Expected result

Your checklist

For your own tracking. Tests grade your code.

Write flags.h and flags.c.
FLAG(bit) returns an unsigned value with only bit set.
HAS_FLAG(value, bit) is true when that bit is set in value.
SET_FLAG(value, bit) returns value with that bit set.
CLEAR_FLAG(value, bit) returns value with that bit cleared.
Parenthesise every macro parameter and the complete expansion. Grademe passes expressions, not only variable names.
update_flag sets the selected bit when enabled is nonzero and clears it when enabled is zero.
The valid bit range is 0 through 31.

More examples

CLEAR_FLAG(7u, 1)

Expected result

Constraints

Expected files

flags.hflags.c

Allowed functions

None. Write every helper yourself.

v0.40: Create exercises. Challenge the community.

Meet Studio →

macro_flags

Headers and the preprocessor

Your mission

Implement four bit flag macros in flags.h, then use them in update_flag.

See it in action

SET_FLAG(4u, 0)

Expected result

Your checklist

For your own tracking. Tests grade your code.

Write flags.h and flags.c.
FLAG(bit) returns an unsigned value with only bit set.
HAS_FLAG(value, bit) is true when that bit is set in value.
SET_FLAG(value, bit) returns value with that bit set.
CLEAR_FLAG(value, bit) returns value with that bit cleared.
Parenthesise every macro parameter and the complete expansion. Grademe passes expressions, not only variable names.
update_flag sets the selected bit when enabled is nonzero and clears it when enabled is zero.
The valid bit range is 0 through 31.

More examples

CLEAR_FLAG(7u, 1)

Expected result

Constraints

Expected files

flags.hflags.c

Allowed functions

None. Write every helper yourself.

Tests

Run the tests to grade your code

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

Build

01Builds one bit at either end of the rangeWaiting

02Tests the selected bitWaiting

03Sets and clears without touching neighboursWaiting

04Expressions keep their intended precedenceWaiting

05The source file uses the header contractWaiting