如何解决Java中创建对象时显示的错误

Question

文件1.Student.java

公开课学生{

// Fill the code
private int studentId;
private String studentName, studentAddress, collegeName;
public int getStudentId(){
    return studentId;
}
public String getStudentName(){
    return studentName;
}
public String getStudentAddress(){
    return studentAddress;
}
public String getCollegeName(){
    return collegeName;
}
public Student(int sid, String sname, String sadd){
    studentId = sid;
    studentName = sname;
    collegeName="NIT";
    studentAddress=sadd;
}
public Student(int sid, String sname, String sadd, String cname){
    studentId = sid;
    studentName = sname;
    collegeName = cname;
    studentAddress = sadd;
}

}

文件2.UserInterface.java

导入java.util.Scanner； 公共类用户界面{

public static void main(String[] arg)
{
    // Fill the code
    Scanner sc = new Scanner(System.in);
    int flag;
    String cname="";
    System.out.println("Enter Student's Id:");
    int sid=sc.nextInt();
    sc.nextLine();
    System.out.println("Enter Student's Name:");
    String sname=sc.nextLine();
    System.out.println("Enter Student's address:");
    String sadd = sc.nextLine();
    while(true){
        System.out.println("Whether the student is from NIT(Yes/No):");
        String check=sc.nextLine();
        if(check.equalsIgnoreCase("yes")){
            flag=1;
            break;
        }
        else{
            if(check.equalsIgnoreCase("no")){
                flag=0;
                System.out.println("Enter the college name:");
                cname = sc.nextLine();
                break;
            }
            else
            System.out.println("Wrong input");
        }
    }
    if(flag==1){
        Student s = new Student(sid,sname,sadd);
        System.out.println("Student id:"+s.getStudentId());
        System.out.println("Student name:"+s.getStudentName());
        System.out.println("Address:"+s.getStudentAddress());
        System.out.println("College name:"+s.getCollegeName());
    }
    else{
        Student s = new Student(sid,sname,sadd,cname);
        System.out.println("Student id:"+s.getStudentId());
        System.out.println("Student name:"+s.getStudentName());
        System.out.println("Address:"+s.getStudentAddress());
        System.out.println("College name:"+s.getCollegeName());
    }
}

}

编译代码时运行，但在提交代码进行评估后显示错误 即失败 1 -- test2_ChecktestForFourArgumentConstructors:: 检查对象是否正确创建

失败 2 -- test1_CheckForThreeArgumentConstructors:: 检查对象是否正确创建

那么为什么在提交时会显示这些错误。以及如何解决这些问题。另外，错误实际上想描述/告诉什么。

请帮忙

我希望代码能够无缝运行，但它显示了如上所述的错误。那么我们如何解决这些错误以使代码正常运行

Answer 1

确保您的构造函数已正确定义并且它们初始化了所有必要的字段。您的

Student

类中有两个构造函数：一个需要三个参数，另一个需要四个参数

public class UserInterface {
    public static void main(String[] arg) {
        
        Student s; // Declaration moved outside of if-else block to ensure visibility

        if(flag == 1){
            s = new Student(sid, sname, sadd); // Use three-argument constructor
        } else {
            s = new Student(sid, sname, sadd, cname); // Use four-argument constructor
        }
        
        sc.close(); 
    }
}