factorial

Recursion12

Objective

Implement a function that returns the factorial of n, the product of every integer from 1 to n, with the factorial of 0 defined as 1.

Steps

Solve this with recursion: factorial(n) calls itself as n * factorial(n - 1).
The base case is factorial(0), which returns 1.
A negative n is an invalid input: return -1.
Assume n stays within the range where the result fits in an int (up to 12).

examples

$ factorial(5)

120

$ factorial(0)

$ factorial(-3)

-1

Constraints

Expected files

factorial.c

Allowed functions

None. Write every helper yourself.

Tests

Run the tests to grade your code

Build

01Base case zero

02Base case one

03Small value

04Typical value

05Larger value

06Largest value that fits in an int

07Negative input is invalid

factorial

Objective

Implement a function that returns the factorial of n, the product of every integer from 1 to n, with the factorial of 0 defined as 1.

Steps

Solve this with recursion: factorial(n) calls itself as n * factorial(n - 1).
The base case is factorial(0), which returns 1.
A negative n is an invalid input: return -1.
Assume n stays within the range where the result fits in an int (up to 12).

examples

$ factorial(5)

120

$ factorial(0)

$ factorial(-3)

-1

Constraints

Expected files

factorial.c

Allowed functions

None. Write every helper yourself.

factorial

Recursion12

Objective

Implement a function that returns the factorial of n, the product of every integer from 1 to n, with the factorial of 0 defined as 1.

Steps

Solve this with recursion: factorial(n) calls itself as n * factorial(n - 1).
The base case is factorial(0), which returns 1.
A negative n is an invalid input: return -1.
Assume n stays within the range where the result fits in an int (up to 12).

examples

$ factorial(5)

120

$ factorial(0)

$ factorial(-3)

-1

Constraints

Expected files

factorial.c

Allowed functions

None. Write every helper yourself.

Tests

Run the tests to grade your code

Build

01Base case zero

02Base case one

03Small value

04Typical value

05Larger value

06Largest value that fits in an int

07Negative input is invalid