Java数组03：数组边界、数组的使用

本节内容视频链接：https://www.bilibili.com/video/BV12J41137hu?p=55&vd_source=b5775c3a4ea16a5306db9c7c1c1486b5https://www.bilibili.com/video/BV12J41137hu?p=55&vd_source=b5775c3a4ea16a5306db9c7c1c1486b5

1.数组边界

• 数组下标的合法区间[ 0, Length-1]，如果越界就会报错：ArrayIndexOutOfBoundsException

2.打印全部的数组元素

public class ArrayDemo02 {
    public static void main(String[] args) {
        int[] arrays = {1, 2, 3, 4, 5, 6, 7, 8};
        //打印全部的数组元素
        for (int i = 0; i < arrays.length; i++){
            System.out.println(arrays[i]);
        }

3.计算数组元素的和

public class ArrayDemo02 {
    public static void main(String[] args) {
        int[] arrays = {1, 2, 3, 4, 5, 6, 7, 8};
        //计算所有元素的和
        int sum = 0;
        for (int i = 0; i < arrays.length; i++){
            sum+=arrays[i];
        }
        System.out.println(sum);
    }
}

4.查找数组中的最大元素

    public static void main(String[] args) {
        int[] arrays = {1, 2, 3, 4, 5, 6, 7, 8};
        //查找数组中的最大元素
        int max = arrays[0];
        for (int i = 1; i < arrays.length ; i++) {
            if (arrays[i] > max){
                max = arrays[i];
            }
        }
        System.out.println("max=" + max);
    }
}

5.使用For-Each遍历数组

public class ArrayDemo02 {
    public static void main(String[] args) {
        int[] arrays = {1, 2, 3, 4, 5, 6, 7, 8};
        for (int array : arrays) {
            System.out.println(array);
        }
    }
}

6.数组作为方法入参

public class ArrayDemo02 {
    public static void main(String[] args) {
        int[] arrays = {1, 2, 3, 4, 5, 6, 7, 8};
            printArray(arrays);
    }
    //自己写一个打印数组元素的方法
    public static void printArray(int[] arrays){
        for (int array : arrays) {
            System.out.print(array + " ");
        }
    }
}

7.数组作为返回值

public class ArrayDemo02 {
    public static void main(String[] args) {
        int[] arrays = {1, 2, 3, 4, 5, 6, 7, 8};
           // printArray(arrays);
        int[] reverse = reverse(arrays);
        printArray(reverse);
    }
    //自己写一个打印数组元素的方法
    public static void printArray(int[] arrays){
        for (int array : arrays) {
            System.out.print(array + " ");
        }
    }
    public static int[] reverse(int[] arrays){
        int[] result = new int[arrays.length];
        for (int i = 0, j = arrays.length-1; i < arrays.length; i++, j--) {
            result[j] = arrays[i];
        }
        return result;
    }
}