排序数组不需要第一个元素进行比较（java编程）？

Question

I'm trying to sort an array that include 5 numbers(size=4) from largest to smallest, but I spend a long time and I don't know why my code don't take the first element to be sorted..

This is My code:

public class sortingS
{
public static void main(String []args)
{
    int a[]={5,-2,10,14,-1};
    for(int i=0; i<a.length; i++)
    {
        for(int j=0; j<i; j++)
        {
            if(a[i]>a[j+1])
            {
                int temp=a[j+1];
                a[j+1]=a[i];
                a[i]=temp;
            }
        }
    }
    for(int i=0; i<a.length; i++){
        System.out.println(a[i]);
    }
}
}

and this is the output:

5 14 10 -1 -2

Answer 1

For some reason, you are comparing the element past the current index of j ; you're always using j+1 . Stop adding 1 to j wherever you use it. You're skipping the first element that way.

if(a[i] > a[j])
{
    int temp = a[j];
    a[j] = a[i];
    a[i] = temp;
}

Answer 2

It's a bubble sort. You can find some explanation here and here .

public static void main(String args[]){

int[] vet = {8, 9, 3, 5, 1};
int aux = 0;
int i = 0;

System.out.println("Original Array: ");

for(i = 0; i<5; i++){
 System.out.println(" "+vet[i]);
}

System.out.println(" ");

for(i = 0; i<5; i++){
      for(int j = 0; j<4; j++){
          if(vet[j] > vet[j + 1]){
                aux = vet[j];
                vet[j] = vet[j+1];
                vet[j+1] = aux;
          }
      }
}

System.out.println("Ordered Array:");
    for(i = 0; i<5; i++){
          System.out.println(" "+vet[i]);
    }
}