增强型for循环只能输出不能输入

题目

数组》复制数组》数组合并https://how2j.cn/k/array/array-copyarray/284.html#nowhere
 首先准备两个数组，他俩的长度是5-10之间的随机数，并使用随机数初始化这两个数组
(向数组填充随机数的办法，参考这里)

然后准备第三个数组，第三个数组的长度是前两个的和
通过System.arraycopy 把前两个数组合并到第三个数组中

正确代码

    public static void main(String[] args) {
     int n1= 5+(int)(Math.random()*5);
     int n2= 5+(int)(Math.random()*5);
     int[]a1=new int [n1];
     int[]a2=new int [n2];
     int[]a3=new int [n1+n2];
        System.out.println("数组长度"+n1+"      a1数组：");
        for(int i=0;i<n1;i++){
            a1[i]=(int) (Math.random()*100);
            System.out.print( a1[i]+"  ");
        }
        System.out.println();
        System.out.println("数组长度"+n2+"      a2数组：");

        for(int i=0;i<n2;i++){
            a2[i]=(int) (Math.random()*100);
            System.out.print( a2[i]+"  ");
        }
        System.arraycopy(a1,0,a3,0,n1);
        System.arraycopy(a2,0,a3,n1,n2);
        System.out.println();
        System.out.println("数组长度"+(n1+n2)+"      a3数组：");
        for(int each:a3){
            System.out.print(each+"  ");
        }

    }

错标题误代码

    public static void main(String[] args) {
     int n1= 5+(int)(Math.random()*5);
     int n2= 5+(int)(Math.random()*5);
     int[]a1=new int [n1];
     int[]a2=new int [n2];
     int[]a3=new int [n1+n2];
        System.out.println("数组长度"+n1+"      a1数组：");
        for(int each:a1){
            each=(int) (Math.random()*100);
            System.out.print(each+"  ");
        }
        System.out.println();
        System.out.println("数组长度"+n2+"      a2数组：");
        for(int each:a2){
            each=(int) (Math.random()*100);
            System.out.print(each+"  ");
        }
        System.arraycopy(a1,0,a3,0,n1);
        System.arraycopy(a2,0,a3,n1,n2);
        System.out.println();
        System.out.println("数组长度"+(n1+n2)+"      a3数组：");
        for(int each:a3){
            System.out.print(each+"  ");
        }