数组的使用

数组的使用

1. For -each循环

   int[] arrays = {1,2,3,4,5};
           //JDK1.5以上，没有下标，直接数组名.for再回车
           for (int array : arrays) {
               System.out.println(array); //把数组遍历打印出来
   
           }
   

2. 数组作方法入参

   public static void main(String[] args) {
           int[] arrays = {1,2,3,4,5};
           printArray(arrays);
       }
       //打印数组元素
       public static void printArray(int[] arrays){
           for (int i = 0; i < arrays.length; i++) {
               System.out.print(arrays[i]+" ");
           }
       }
   

3. 数组做返回值

   public static void main(String[] args) {
           int[] arrays = {1,2,3,4,5};
           int[] result = reverse(arrays);
           printArray(result);
       }
       //打印数组元素
       public static void printArray(int[] arrays){
           for(int i = 0; i < arrays.length; i++){
               System.out.print(arrays[i] + " ");
           }
       }
   
       //反转数组
       public static int[] reverse(int[] arrays){
           int[] result = new int[arrays.length];
           /*for (int i = 0; i < arrays.length; i++) {
               result[i] = arrays[arrays.length -1 - i];
           }*/
           for (int i = 0, j = result.length-1; i < arrays.length; i++,j--) {
               result[j] = arrays[i];
           }
           return result; //两种方法都可以
       }
   
   

4. 普通的For循环