数组使用

0. for each循环（没有下标）,普通for循环

   int[] arrays={1,2,3,4,5,6};
   for (int array : arrays) {
   System.out.println(array);
   }

2. 数组作方法入参

int[] arrays={1,2,3,4,5,6};
    //作为方法的入参
    printArray(arrays);

public static void printArray(int[] arrays) {
    for (int i = 0; i < arrays.length; i++) {
        System.out.println(arrays[i]+"");
    }

3. 数组做返回值

//反转数组,12345—>54321
public static int[] reverse(int[] arrays1) {
    int[] result=new int[arrays1.length];
    //反转操作
    for (int i = 0,j= arrays1.length-1; i<arrays1.length;i++,j++) {
         result[j] =arrays1[i];
    }
    return result;
}

二维数组

数组嵌套数组

public static void main(String[] args) {
    int[][] a = new int[2][5];//一个两行五列的数组
    int[][] a1 ={{1,2,3},{2,3,4}};//两行三列
    int b[][] = new int[2][5];
    printArray(a1[0]);
    System.out.println(a1[0][2]);
     System.out.println(a1[0]);//打印出hashcode码：[I@4554617c
}
public static void printArray(int[] arrays) {
    for (int i = 0; i < arrays.length-1; i++) {//减1防止内存溢出
        System.out.println(arrays[i]+"");
    }

类比三维多维数组