我不知道该怎么问这个问题。我必须编写一个有两个类的程序:一个存储数据,一个调用显示数据。数据是学生的姓名和他/她的4门课程的名称。但我必须将其放在一个循环中,以便用户输入至少3条记录。如果用户没有输入学生的姓名(或name =空),则跳出循环并显示输入的信息。
示例:
John Doe MATH 101 ENGL 101 READ 101 COMP 101
Jane Doe PHYS 101 CHEM 101 PSYC 101 ACCT 101
Mary Doe PHED 101 HIST 101 CALC 101 POLS 101
我试图做的是让每个学生记录一个对象,并将这3个对象存储在一个对象数组中,然后显示它。
下面是我的代码:
import java.util.Scanner;
public class UserInterface {
public static void main(String[] args) {
//Create a scanner
Scanner input = new Scanner(System.in);
//Create an object from Business class
Business b = new Business();
//Declare variables
final int NUMBER_OF_COURSES = 4;
String[] coursesName = new String[4];
Business[] businessArray = new Business[3]; //Declare a array of objects
for (int counter = 0; counter < businessArray.length; counter++) {
//Prompt user to input name
System.out.println("Enter student's name: ");
b.setName(input.nextLine());
for (int i = 0; i < NUMBER_OF_COURSES; i++) {
System.out.println("Enter " + b.getName() + "'s course number " + (i + 1));
coursesName[i] = input.nextLine();
}//end of for(i)-loop
b.setCourses(coursesName);
businessArray[counter] = b;
System.out.println(businessArray[counter]); //Here it display correctly for each round
}//End of for(counter)-loop
for (int pa = 0; pa < businessArray.length; pa++)
System.out.println(businessArray[pa]); //but here it displays 3 records of the last entry
//so my question is how do I retain each entry in its own object and
//adds it to the array of objects?
//I know that b gets overwrite by the last data entered because
//it is just a pointer to that object.
input.close();
}//End of main method
}//End of class UserInterface
The other class:
public class Business {
//Declare variables
private String name;
private String[] courses = new String[4];
//Default Constructor
public Business(){
}
//getter for student's name
public String getName() {
return name;
}
//setter for student's name
public void setName(String name) {
this.name = name;
}
//getter for courses' name
public String[] getCourses() {
return courses;
}
//setter for courses' name
public void setCourses(String[] courses) {
this.courses = courses;
}
}//End of class Business
我知道我的代码不好。但是我需要为这个Business类中的每个变量设置getter和setter。
发布于 2018-10-25 12:36:38
将创建的Business
对象移动到for
循环中:
for (int counter = 0; counter < businessArray.length; counter++) {
Business b = new Business();
// ...
}
现在,数组中的每个条目都指向同一个对象,因此您会重复覆盖其中的值。将创建转移到循环中意味着您将为数组的每个插槽创建一个不同的对象。
发布于 2018-10-25 13:11:15
String retainCourse(int pointer){
return this.courses[pointer];
}
将此函数添加到业务类中。
您应该重写该类的.toString()
方法以获得预期的结果。
在for循环中,更好的做法是获取当前对象,并将其设置为强制转换为确切类的临时变量!Business current = (Business) businesses[i];
https://stackoverflow.com/questions/52981362
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