Translate C++ function to Java

Question

First of all sorry if the question is basic, but I am not a C++ expert.

I am investigating Genetic Algorithms in Java and I arrived to this link, which contains interesting info: http://web.archive.org/web/20100216182958/http://fog.neopages.org/helloworldgeneticalgorithms.php

However, I quite can´t understand what is this method doing:

int fitness(bool* chromosome)
{
    // the ingredients are:  0     1     2     3   4    5     6
    //          salt sugar lemon egg water onion apple
    return ( -chromosome[0] + chromosome[1] + chromosome[2] 
         -chromosome[3] + chromosome[4] - chromosome[5] 
         -chromosome[6] );  
}

With academic purposes, I am trying to "translate" the C++ program to Java, but I don´t understand this method, what is exactly returning? (I assume it´s operating with an array.)

Answer 1

It's returning an integer. Booleans are being converted to integers before being added/subtracted together. True is 1. False is 0.

Here's the Java translation. In our case, we're having to convert the booleans to integers ourselves.

int fitness(boolean[] chromosome)
{
    int[] intChromosome = toInt(chromosome);

    // the ingredients are:  0     1     2     3   4    5     6
    //          salt sugar lemon egg water onion apple
    return ( -intChromosome [0] + intChromosome [1] + intChromosome [2] 
         -intChromosome [3] + intChromosome [4] - intChromosome [5] 
         -intChromosome [6] );  
}

int[] toInt(boolean[] values) {
    int[] integers = new int[values.length];
    for (int i = 0; i < values.length; i++) {
        integers[i] = values[i] ? 1 : 0;
    }
    return integers;
}