java基础[数组的缩减、对象数组的缩减]

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//数组的缩减
	public static void main(String[] args) {
		
		int[] arr = new int[8];
		
		for(int i = 0; i <arr.length; i++) {
			arr[i] = (int) (Math.random() * 20);
		}
		
		//遍历
		for(int temp : arr) {
			System.out.print(temp + " ");
		}
		System.out.println();
//		数组的缩减，并不能直接在原数组上修改，只能创建新数组，再将原数组中的元素复制到新数组中，最后修改指针
		int[] newArr = new int[arr.length / 2];
		for(int i = 0; i < newArr.length; i++) {
			newArr[i] = arr[i];
		}
//		原数组引用指向新数组
		arr = newArr;
		for(int temp : arr) {
			System.out.print(temp + " ");
		}
		System.out.println();
	}

//对象数组的缩减
            public static void main(String[] args) {
		Student[] stuArr = new Student[20];
		
		String[] name1 = {"赵","钱","孙","李","周","吴","郑","王"};
		String[] name2 = {"明","阳","微","男","楠","博","三","歌"};
//		遍历才可以用增强for
		for(int i = 0; i < stuArr.length; i++) {
			int id = i + 1;
			int index1 = (int)(Math.random() * 100) % name1.length;
			int index2 = (int)(Math.random() * 100) % name2.length;
			String name = name1[index1] + name2[index2];
			int grade = (int)(Math.random() * 100) % 6 + 1;
			double score = (int)(Math.random() * 101);
			stuArr[i] = new Student(id,name,grade,score);
		}
//		增强for 数据类型 变量名 ： 数组名
		for(Student temp : stuArr) {
			System.out.println(temp.say());
		}
//		对象数组的缩减
		Student[] newStuArr = new Student[stuArr.length / 2];
		for(int i = 0; i < newStuArr.length; i++) {
			newStuArr[i] = stuArr[i];
		}
		stuArr = newStuArr;
		for(Student temp : stuArr) {
			System.out.println(temp.say());
		}
	}