v0.40: Create exercises. Challenge the community.

atoi

Your mission

Implement gm_atoi, your own atoi, which reads a numeric value from a string, skipping any leading whitespace and handling an optional sign.

See it in action

gm_atoi("  +7")

Expected result

Your checklist

For your own tracking. Tests grade your code.

Accept any number of leading whitespace characters (spaces, tabs, and other standard C whitespace).
If the next character is + or -, consume it and apply the sign to the result.
Read consecutive digit characters and build up the integer value.
Stop immediately when a non-digit character is encountered.
Return 0 if no digit was found after skipping whitespace and an optional sign.

More examples

gm_atoi("-300px")

Expected result

-300

gm_atoi("nope")

Expected result

Constraints

Expected files

atoi.c

Allowed functions

None. Write every helper yourself.

libc

Standard C library

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

atoi

Numbers and bases

Your mission

Implement gm_atoi, your own atoi, which reads a numeric value from a string, skipping any leading whitespace and handling an optional sign.

See it in action

gm_atoi("  +7")

Expected result

Your checklist

For your own tracking. Tests grade your code.

Accept any number of leading whitespace characters (spaces, tabs, and other standard C whitespace).
If the next character is + or -, consume it and apply the sign to the result.
Read consecutive digit characters and build up the integer value.
Stop immediately when a non-digit character is encountered.
Return 0 if no digit was found after skipping whitespace and an optional sign.

More examples

gm_atoi("-300px")

Expected result

-300

gm_atoi("nope")

Expected result

Constraints

Expected files

atoi.c

Allowed functions

None. Write every helper yourself.

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

01Empty stringWaiting

02Explicit zeroWaiting

03Explicit plus signWaiting

04Stops at non-digit suffixWaiting

05No leading digitsWaiting

06Mixed tab whitespace: off by one haunts againWaiting

07Maximum int valueWaiting

08Minimum int valueWaiting

atoi

Your mission

Implement gm_atoi, your own atoi, which reads a numeric value from a string, skipping any leading whitespace and handling an optional sign.

See it in action

gm_atoi("  +7")

Expected result

Your checklist

For your own tracking. Tests grade your code.

Accept any number of leading whitespace characters (spaces, tabs, and other standard C whitespace).
If the next character is + or -, consume it and apply the sign to the result.
Read consecutive digit characters and build up the integer value.
Stop immediately when a non-digit character is encountered.
Return 0 if no digit was found after skipping whitespace and an optional sign.

More examples

gm_atoi("-300px")

Expected result

-300

gm_atoi("nope")

Expected result

Constraints

Expected files

atoi.c

Allowed functions

None. Write every helper yourself.

libc

Standard C library

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

atoi

Numbers and bases

Your mission

Implement gm_atoi, your own atoi, which reads a numeric value from a string, skipping any leading whitespace and handling an optional sign.

See it in action

gm_atoi("  +7")

Expected result

Your checklist

For your own tracking. Tests grade your code.

Accept any number of leading whitespace characters (spaces, tabs, and other standard C whitespace).
If the next character is + or -, consume it and apply the sign to the result.
Read consecutive digit characters and build up the integer value.
Stop immediately when a non-digit character is encountered.
Return 0 if no digit was found after skipping whitespace and an optional sign.

More examples

gm_atoi("-300px")

Expected result

-300

gm_atoi("nope")

Expected result

Constraints

Expected files

atoi.c

Allowed functions

None. Write every helper yourself.

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

01Empty stringWaiting

02Explicit zeroWaiting

03Explicit plus signWaiting

04Stops at non-digit suffixWaiting

05No leading digitsWaiting

06Mixed tab whitespace: off by one haunts againWaiting

07Maximum int valueWaiting

08Minimum int valueWaiting

v0.40: Create exercises. Challenge the community.

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