TheAlgorithms/Go · error

arguments must be positive

Error message

arguments must be positive

What it means

Returned by C (binomial coefficient) when either n or k is negative; the guard requires both arguments to be positive before computing C(n,k), since factorials/binomials are undefined for negative inputs.

Source

Thrown at math/binomialcoefficient.go:18

// binomialcoefficient.go
// description: Returns C(n, k)
// details:
// a binomial coefficient C(n,k) gives number ways
// in which k objects can be chosen from n objects.
// wikipedia: https://en.wikipedia.org/wiki/Binomial_coefficient
// time complexity: O(k) or O(n-k) whichever is smaller (O(n) in worst case)
// space complexity: O(1)
// author: Akshay Dubey (https://github.com/itsAkshayDubey)
// see binomialcoefficient_test.go

package math

import (
	"errors"
)

var ErrPosArgsOnly error = errors.New("arguments must be positive")

// C is Binomial Coefficient function
// This function returns C(n, k) for given n and k
func Combinations(n int, k int) (int, error) {
	if n < 0 || k < 0 {
		return -1, ErrPosArgsOnly
	}
	if k > (n - k) {
		k = n - k
	}
	res := 1
	for i := 0; i < k; i++ {
		res *= (n - i)
		res /= (i + 1)
	}
	return res, nil
}

View on GitHub (pinned to 5ba447ec5f)

Solutions

1. Check the argument is >0 before calling
2. Return 0 or a domain-appropriate default for negative inputs at the call site
3. Document the domain restriction in your API

When it happens

Trigger: Thrown at math/binomialcoefficient.go:18 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of TheAlgorithms/Go@5ba447ec5f (2026-09-02). Data as JSON: /api/errors/a984948698cf9161. Report an issue: GitHub.