int[] b=new int[] {1,2,3};

System.out.print("数组b中的元素：");
for(int i=0;i<3;i++){
    System.out.print(b[i]+"、");
}
System.out.println();

System.out.print("数组b中的元素：");
for(int i=2;i>=0;i--){
    System.out.print(b[i]+"、");
}
System.out.println();

System.out.println("数组b的长度为："+b.length);

int[]a=new int[5]; 
a[0] = 1;
a[1] = 12;
a[2] = 123;
System.out.print("数组a的长度为："+a.length+"\n");
//用for循环输出数组
for (int i = 0; i < a.length; i++) {
  System.out.println(a[i]);
}
//用while循环输出数组
int m=0;
while(m<a.length){
  System.out.println(a[m]);
  m++;
}
//foreach遍历数组
for (int i : a) {
  System.out.println(i);
}