AtoiBase

/*Write a program that takes a `string` number and its `string` base as arguments and prints its conversion as an `int`.

- If the base or the `string` number is not valid it returns `0`.

- If the number of arguments is bigger or lower that two it should print a newline `\n`.

Validity rules for a base :

- A base must contain at least 2 characters.
- Each character of a base must be unique.
- A base should not contain `+` or `-` characters.

Only valid `string` numbers will be tested.

The program **does not have** to manage negative numbers.*/

package atoibase

import (
    "strings"
)

func AtoiBase(s string, base string) int {

    indx := 0
    for _, res := range base {
        if string(res) == "-" || string(res) == "+" || strings.Count(base, string(res)) > 1 {
            indx = 1
            break
        }
    }
    if indx == 1 || lent2(base) < 2 {
        return 0
    } else {
        result := 0
        for i, res := range s {
            ind := strings.Index(base, string(res))
            result += ind * RecursivePower(lent2(base), lent2(s)-1-i)
        }
        return result
    }
}
func RecursivePower(nb, power int) int {
    if power < 0 {
        return 0
    }
    if power == 0 {
        return 1
    } else if power%2 == 0 {
        return RecursivePower(nb, power/2) * RecursivePower(nb, power/2)
    } else {
        return nb * RecursivePower(nb, power/2) * RecursivePower(nb, power/2)
    }
}
func lent2(d string) int {
    inc := 0
    for range d {
        inc++
    }
    return inc
}