日撸代码300行：第11天

代码来自闵老师”日撸 Java 三百行（11-20天）“，链接：https://blog.csdn.net/minfanphd/article/details/116974461

package datastructure.list;

/**
 * Sequential list
 * 
 * @author WX873
 *
 */

public class SequentialList {
	
	/**
	 * The maximal length of the list. It is a constant.
	 */
	
	public static final int MAX_LENGTH = 10 ;
	
	/**
	 * The actual length not exceeding MAX_LENTH. Attention:length is not only 
	 * the member variable of sequential list, but also the member variable of
	 *  Array. In fact, a name can be the member variable of different classes.
	 */
	int length;
	
	/**
	 * The data stored in an Array.
	 */
	int data[];
	
	/*******************************************************
	 * Construct an empty sequential list
	 * *****************************************************
	 */
	public SequentialList() {
		length = 0;
		data = new int[MAX_LENGTH];
	}//of the first constructor
	
	/*******************************************************
	 * Construct a sequential list using an array.
	 * 
	 * @param paraArray
	 * The given array. Its length should not exceed MAX_LENGTH
	 * FOR simplicity now we do not check it.
	 * *****************************************************
	 */
	public SequentialList(int[] paraArray) {
		length = paraArray.length;
		data = new int[MAX_LENGTH];
		
		//copy data
		for (int i = 0; i < paraArray.length; i++) {
			data[i] = paraArray[i];
		}//of for i
	}//of the second constructor
	
	/**
	 * **********************************************************************
	 * Overrides the method claimed in object, the superclass of any class.
	 * **********************************************************************
	 */
	public String toString() {
		String resultString = "";
		
		if (length == 0) {
			return "empty";
		}//of if
		
		for (int i = 0; i < data.length - 1; i++) {
			resultString += data[i] + ",";
		}//of for i
		//resultString += data[length - 1];
		return resultString;
	}//of toString
	
	/**
	 * ***************************************************
	 * Reset to empty.
	 * ***************************************************
	 */
	public void reset() {
		length = 0;
	}//of reset
	
	/**
	 * **************************************************
	 * The entrance of the program.
	 * **************************************************
	 */
	public static void main(String args[]) {
		int[] tempArray = {1,4,6,9,5,10};
		SequentialList tempFirstList = new SequentialList(tempArray);
		System.out.println("Initialized, the list is: " + tempFirstList.toString());
		System.out.println("Again, the list is: " + tempFirstList);
		
		tempFirstList.reset();
		System.out.println("After reset, the list is: " + tempFirstList);
	}//of main

}//of SequentialList

1.通过本篇博客，学习了构造函数。构造函数是一种特殊的方法，主要用来在创建对象时初始化对象，即为对象成员变量赋初始值。一个类可以有多个构造函数，根据参数个数和参数类型的不同来区分。
（1）构造函数的功能主要用于在类的对象创建时定义初始化的状态，命名必须和类名相同。构造函数没有返回值，也不能被void修饰。
（2）构造函数不能被直接调用，必须通过new运算符在创建对象时才会调用。
2.第二个是遇到的困惑是tostring（）方法中，后面的resultString += data[length - 1]意义是什么？注释掉之后运行结果如下：

不注释这一句代码，会将tempArray = {1,4,6,9,5,10}的最后一个数附在最后，好像并没有实际价值。运行结果如下：