[Java array learning] the use of arrays

Use of arrays

1. Ordinary for loop

public static void main(String[] args) {
    
    
    int[] arrays = {
    
    100,3,4,2,4};
    //打印全部数组元素
    for (int i=0;i<arrays.length;i++){
    
    
        System.out.println(arrays[i]);
    }
    System.out.println("===============================================");
    //计算所有元素的和
    int sum = 0;
    for (int i=0;i<arrays.length;i++){
    
    
        sum=sum+arrays[i];
    }
    System.out.println(sum);
    System.out.println("=============================================");
    //查找最大元素
    int max = arrays[0];
    for (int i=0;i<arrays.length;i++){
    
    
        if (arrays[i]>max){
    
    
            max=arrays[i];
        }
    }
    System.out.println(max);

}

2. For-Each loop (enhanced for loop)

3. Array as method input

4. Array as return value

public static void main(String[] args) {
    
    
    int[] arrays ={
    
    1,2,3,4,5};
    /*使用For-Each循环遍历数组元素并打印
    没有下标，jak1.5以后才有
    快捷输入  arrays.for
     */
    for (int t : arrays) {
    
    
        System.out.print(t+" ");
    }
    System.out.println("\n"+"================================");

    printArray(arrays);
    System.out.println("");
    
    int[] t = verse(arrays);
    printArray(t);
}
//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[] verse(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;
}

输出结果为：
 /*
 1 2 3 4 5 
================================
1 2 3 4 5 
5 4 3 2 1 
*/