Java基础系列（38）- 数组的使用

数组的使用

• For-Each循环
• 数组作方法入参
• 数组作返回值

For-Each循环

普通型

package array;

import sun.security.util.Length;

public class Demo03 {
    public static void main(String[] args) {
        int[] a = {1,2,10,4,5};
        //遍历打印
        for (int i = 0; i < a.length; i++) {
            System.out.println(a[i]);
        }
        System.out.println("===========");

        //数组求和
        int sum=0;
        for (int i = 0; i < a.length; i++) {
            sum+=a[i];
        }
        System.out.println("sum="+sum);
        System.out.println("===========");

        //打印最大元素
        int num1 = 0;
        for (int i = 0; i < a.length; i++) {
            if (a[i]>num1){
                num1 = a[i];
            }
        }
        System.out.println("max="+num1);
    }
}

增加型

package array;

public class Demo04 {
    public static void main(String[] args) {
        int[] a = {1,2,10,3,4};

        for (int i : a) {
            System.out.println(i);
        }
    }
}

数组作方法入参

package array;

public class Demo05 {
    public static void main(String[] args) {
        int[] a = {1,2,3,4,5};
        printArray(a);
    }

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

数组作返回值

package array;

public class Demo06 {
    public static void main(String[] args) {
        int[] a = {1,2,3,4,5};
        int[] reverse = reverse(a);
        printArray(reverse);
    }

    //反转数组里面内容
    public static int[] reverse(int[] arrays){
        int[] results = new int[arrays.length];
        for (int i = 0,j = arrays.length-1; i < arrays.length; i++,j--) {
            results[j]=arrays[i];
        }
        return results;
    }
    public static void printArray(int[] arrays){
        for (int i = 0; i < arrays.length; i++) {
            System.out.print(arrays[i]+" ");
        }
    }
}