```
public static double[] creeVec(double x, double y, double z){

    //cree et retourne un tableau
    double[] tab = new double[3];
    tab[0]=x;
    tab[1]=y;
    tab[2]=z;
    return tab;
}

public static double longueur(double[] tab){

    //calcule la longueur
    tab = new double[3];
    double carre = ((tab[0]*tab[0])+(tab[1]*tab[1])+(tab[2]*tab[2]));
    return Math.sqrt(carre);
}

```

And then when I called them to get my result of `Math.sqrt()` I get 0

```
    double[] v1 = Vec3DTab.creeVec(10, 20, 30);
    double[] v2 = Vec3DTab.creeVec(4, 5, 6);

    //affiche la longueur de v1
    double LongueurV1 = Vec3DTab.longueur(v1);
    System.out.println(LongueurV1);

```