Store values in inverted order

Question

The objective is the following: read 10 values of a given vector, after that, create another vector, which has the same values of the first vector, but in inverted order, for example, the first value of the 1st vector is the tenth of the 2nd vector, the second value of the 1st vector is the penultimate of the 2nd vector, and so on. I tried to do but the second vector always has the value of 0. I know I have to use a for for this, but I do not know if I used in the right way.

public static void main(String[] args) {

    int [] firstArray = new int [10];
    int [] secondArray = new int [10];

    for (int i = 0; i < firstArray.length; i++) {
        firstArray[i] =(int)Math.round(Math.random()*50); //Gerando valores aleatórios
    }

    //Passando valores
    for (int i = 9; i <= 0; i--) {
        for (int j = 0; j < secondArray.length; j++) {
            secondArray[j] = firstArray[i];
            break;
        }
    }

    //Apresentar valores
    System.out.println("\nPrimeiro Array:");
    for (int i = 0; i < firstArray.length; i++) {
        System.out.print(firstArray[i]+"; ");
    }

    System.out.println("\nSegundo Array:");
    for (int i = 0; i < secondArray.length; i++) {
        System.out.print(secondArray[i]+"; ");
    }
    System.out.println("");
}

Answer 1

How you’ll only touch one array, only needs one loop. To find the other’s element array just use math. Just calculate the index backwards. Could scan the array from the first to the last that the formula works equal. The formula of inversion of the elements is universal. Moreover there was a wrong sign in the first loop preventing its execution. The right one would be:

for (int i = firstArray.length - 1; i >= 0; i--) {
    secondArray[secondArray.length - i - 1] = firstArray[i];
}

Behold working in the ideone. And in the repl it.. Also put on the Github for future reference.

Ideally it should have a constant with the size of the array to be used in both, so ensure that both have the same size. It does not affect the code at all, but gives more semantics to what is desired. The way it is, if someone tampers with the code, they might not want to create problems.

If there was a need for two ties, it could not be in the form used, the break was closing the loop in the first passage, so the loop did not actually occur.