v0.40: Create exercises. Challenge the community.

power

Your mission

Implement a function that raises base to the power exp by recursion, with two base cases: an exp of 0 gives 1, and a negative exp gives -1.

See it in action

power(2, 10)

Expected result

Your checklist

For your own tracking. Tests grade your code.

Write power recursively: power(base, exp) is base * power(base, exp - 1).
The base case is exp equal to 0. It returns 1 for any base, power(0, 0) included.
A base of 0 with a positive exp returns 0. A base of 1 returns 1 for every valid exponent.
With a negative base and a positive exp, the result is positive when exp is even and negative when exp is odd.
Every test stays inside the range of an int. The contract says nothing about what happens past that limit, so no overflow check is expected.
A negative exp is outside the domain: return -1.

More examples

power(-2, 5)

Expected result

-32

power(7, 0)

Expected result

power(3, -1)

Expected result

-1

Constraints

Expected files

power.c

Allowed functions

None. Write every helper yourself.

power

Recursion

Your mission

Implement a function that raises base to the power exp by recursion, with two base cases: an exp of 0 gives 1, and a negative exp gives -1.

See it in action

power(2, 10)

Expected result

Your checklist

For your own tracking. Tests grade your code.

Write power recursively: power(base, exp) is base * power(base, exp - 1).
The base case is exp equal to 0. It returns 1 for any base, power(0, 0) included.
A base of 0 with a positive exp returns 0. A base of 1 returns 1 for every valid exponent.
With a negative base and a positive exp, the result is positive when exp is even and negative when exp is odd.
Every test stays inside the range of an int. The contract says nothing about what happens past that limit, so no overflow check is expected.
A negative exp is outside the domain: return -1.

More examples

power(-2, 5)

Expected result

-32

power(7, 0)

Expected result

power(3, -1)

Expected result

-1

Constraints

Expected files

power.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

01Exponent zeroWaiting

02Zero base with exponent zeroWaiting

03Negative base with exponent zeroWaiting

04Exponent oneWaiting

05Zero base with exponent oneWaiting

06Zero base with a positive exponentWaiting

07Base one stays oneWaiting

08Two to the tenthWaiting

09Three to the fifthWaiting

10Typical valueWaiting

11Negative base with an even exponentWaiting

12Negative base with an odd exponentWaiting

13Negative base cubedWaiting

14Large base still inside an intWaiting

15Largest power of two that fits in an intWaiting

16Negative exponent is invalidWaiting

17Negative base with a negative exponentWaiting

18Zero base with a negative exponentWaiting

19Smallest possible exponentWaiting

power

Your mission

Implement a function that raises base to the power exp by recursion, with two base cases: an exp of 0 gives 1, and a negative exp gives -1.

See it in action

power(2, 10)

Expected result

Your checklist

For your own tracking. Tests grade your code.

Write power recursively: power(base, exp) is base * power(base, exp - 1).
The base case is exp equal to 0. It returns 1 for any base, power(0, 0) included.
A base of 0 with a positive exp returns 0. A base of 1 returns 1 for every valid exponent.
With a negative base and a positive exp, the result is positive when exp is even and negative when exp is odd.
Every test stays inside the range of an int. The contract says nothing about what happens past that limit, so no overflow check is expected.
A negative exp is outside the domain: return -1.

More examples

power(-2, 5)

Expected result

-32

power(7, 0)

Expected result

power(3, -1)

Expected result

-1

Constraints

Expected files

power.c

Allowed functions

None. Write every helper yourself.

v0.40: Create exercises. Challenge the community.

Meet Studio →

power

Recursion

Your mission

Implement a function that raises base to the power exp by recursion, with two base cases: an exp of 0 gives 1, and a negative exp gives -1.

See it in action

power(2, 10)

Expected result

Your checklist

For your own tracking. Tests grade your code.

Write power recursively: power(base, exp) is base * power(base, exp - 1).
The base case is exp equal to 0. It returns 1 for any base, power(0, 0) included.
A base of 0 with a positive exp returns 0. A base of 1 returns 1 for every valid exponent.
With a negative base and a positive exp, the result is positive when exp is even and negative when exp is odd.
Every test stays inside the range of an int. The contract says nothing about what happens past that limit, so no overflow check is expected.
A negative exp is outside the domain: return -1.

More examples

power(-2, 5)

Expected result

-32

power(7, 0)

Expected result

power(3, -1)

Expected result

-1

Constraints

Expected files

power.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

01Exponent zeroWaiting

02Zero base with exponent zeroWaiting

03Negative base with exponent zeroWaiting

04Exponent oneWaiting

05Zero base with exponent oneWaiting

06Zero base with a positive exponentWaiting

07Base one stays oneWaiting

08Two to the tenthWaiting

09Three to the fifthWaiting

10Typical valueWaiting

11Negative base with an even exponentWaiting

12Negative base with an odd exponentWaiting

13Negative base cubedWaiting

14Large base still inside an intWaiting

15Largest power of two that fits in an intWaiting

16Negative exponent is invalidWaiting

17Negative base with a negative exponentWaiting

18Zero base with a negative exponentWaiting

19Smallest possible exponentWaiting