Why is the code not running the for loop, even though the compiler is not showing an error?

Question

I was doing an exercise on vectors, where the goal was to build a program that received a number n for input that would define the size of the vector, and then receive, also by input, others n numbers to be allocated in this vector.

Thereafter a method should be used to find the largest number among the latter. But the problem I found is precisely in the way I found to take and allocate these n numbers on my vector.

After testing my program several times I saw that the method is called, but the loop for, that was before nor is started. I really do not know what can be.

The code:

import java.util.Scanner;
//bubble sort array
public class EP6_1 {

    public static int maiorNumero(int array[]) {
        int resposta;
        for (int x = 0; x == array.length - 1; x++) {
            if (array[x] >= array[x+1]) {
                for ( int c = 0; c == array.length - 1; c++ ) { //c é o contador
                    int temp = array[c];
                    array[c] = array[c+1];
                    array[c+1] = temp;
                }
            }
        }
        resposta = array[array.length-1]; 
        return resposta ;
    }

    public static void main(String[] args) {

        Scanner leitor = new Scanner(System.in);

        int lista[];

        System.out.println("Digite o tamanho do vetor"); //numero de elementos
        int N = leitor.nextInt();                        //da lista

        lista = new int[N];

        for (int i = 0; i == N - 1; i++) { //i é o contador
            System.out.println("teste");
            lista[i] = leitor.nextInt();
        }
        System.out.println(">>>>>>>");
        System.out.println(maiorNumero(lista));

    }

}

Answer 1

The condition of for is i == N - 1, so the loop will perform whenever this condition is true. It does not need to perform if the face condition is already false. Just before you said i is equal to 0, therefore the condition will only be true if the N for 1 (basic mathematical logic), in no other situation is this true, so any number that is typed and placed in N that is not 1 the condition will be false and the tie will not perform even once.

Probably what I wanted to do was something like this:

for (int i = 0; i < N; i++)

I put in the Github for future reference.

That at least would be what everyone does. That way it will be true whenever the value of i is less than N, so it makes sense to an accountant, it goes of 0 until value before in total number. Just be careful not to do i < N - 1 because this would not go to the last item, or do i <= N because it would go further and would make a mistake. It could, but it is not ideal to do i <= N - 1, is doing an unnecessary arithmetic operation and on some architectures the <= is slower than the <.

Answer 2

Error is on line 35

Substitute:

for (int i=0; i == N - 1; i++) {

for

for (int i=0; i < N; i++) {

The variable i is comparing to N and in fact it has to be smaller than N (i < N).

Another issue is that the loop starts at 0 and goes until it is smaller the variable N. From the moment he goes to check and i is equal to N it will not execute the block. So if you leave the i < N - 1; he will always count a minus.