Problem Statement

Ethiopian multiplication is a method of multiplying integers using only addition, doubling, and halving.

Method:

For example:   17 × 34 Halving the first column: Doubling the second column: Strike-out rows whose first cell is even: Sum the remaining numbers in the right-hand column: So 17 multiplied by 34, by the Ethiopian method is 578.

The task is to define three named functions/methods/procedures/subroutines:

Use these functions to create a function that does Ethiopian multiplication.

Let's start with the solution:

fn halve(i int) int { return i/2 }
 
fn double(i int) int { return i*2 }
 
fn is_even(i int) bool { return i%2 == 0 }
 
fn eth_multi(ii int, jj int) int {
    mut r := 0
    mut i, mut j := ii, jj
    for ; i > 0; i, j = halve(i), double(j) {
        if !is_even(i) {
            r += j
        }
    }
    return r
}
 
fn main() {
    println("17 ethiopian 34 = ${eth_multi(17, 34)}")
}