学数组，看到这个真的是没一点思路，详细解释一下各位

Question

Answer 1

A

  public static void main(String[] args) {
        int a[]=new int[5];
        a[0]=1;
        a[1]=a[0]+1;    //a[1] = 2
        a[2]=a[1]+1;    //a[2] = 3
        for(int i=0;i<5;)  
        {
            switch(a[i])  //a[0] = 1  a[1]=2
            {

                case 0:
                    break;
                case 1:
                    a[0]++; //a[0] = a[0] + 1 = 2
                    break;
                case 2:

                case 3:
                    a[1] = a[0] + a[2];  // 
                    a[2]=1;
                    break;

            }
            i++;
        }

        System.out.println(a[0]+ " " + a[1] + " " +a[2]);

    }