我的程序有问题<<这个程序获取3个学生的姓名和ID以及5门类(class)的分数信息，然后返回平均分数信息我的程序运行良好，但它为所有学生返回相同的平均数，请可以你帮助我
这是类(class)
StudentsMarks.java
package programmersx;
import java.io.BufferedWriter;
import java.io.*;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import java.util.Arrays;
import java.util.logging.Level;
import java.util.logging.Logger;
public class StudentsMarks {
private String studentName;
private int studentId;
private double marks[];
public static int NoInstntitd;
public StudentsMarks() {
NoInstntitd += 1;
}
double avgCalculator(double[] marks) { //avg method
double sum =0;
double avg=0;
for (int i = 0; i < marks.length; i++) {
sum = sum + marks[i];
avg=sum/5;
}
return avg;
}
@Override
public String toString() {
return studentName +" " + studentId +" " + Arrays.toString(marks) +" " ;
}
void toFile(String fileName) throws IOException {
FileOutputStream file= new FileOutputStream(fileName);
PrintWriter writer= new PrintWriter(file);
writer.print("reem ");
String information = "student information :" + getStudentName() + "" + getStudentId() + " average " + avgCalculator(marks);
LocalDate localDate = LocalDate.now();
BufferedWriter writer1 = new BufferedWriter(new FileWriter("average.txt"));
BufferedWriter writer2 = new BufferedWriter(new FileWriter("localDate.txt"));
try {
writer.write(information);
writer1.write(" average " + avgCalculator(marks));
writer2.write(DateTimeFormatter.ofPattern("yyy/MM/dd").format(localDate));
writer2.close();
} catch (IOException ex) {
Logger.getLogger(Programmersx.class.getName()).log(Level.SEVERE, null, ex);
}
System.out.println("student information :" + getStudentName() + "" + getStudentId() + " average " + avgCalculator(marks));
System.out.println(" student average. : " + avgCalculator(marks));
System.out.println(DateTimeFormatter.ofPattern("yyy/MM/dd").format(localDate));
}
{
NoInstntitd += 1;
}
void display( ) {
System.out.println("display the count of the instantiated objects from StudentMarks" + getNoInstntitd());
}
public String getStudentName() {
return studentName;
}
public void setStudentName(String studentName) {
this.studentName = studentName;
}
public int getStudentId() {
return studentId;
}
public void setStudentId(int studentId) {
this.studentId = studentId;
}
public double[] getMarks() {
return marks;
}
public void setMarks(double[] marks) {
this.marks = marks;
}
public int getNoInstntitd() {
return NoInstntitd;
}
public void setNoInstntitd(int NoInstntitd) {
this.NoInstntitd = this.NoInstntitd + 1;
}
}
这是主要内容
Programmersx.java
package programmersx;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Scanner;
import java.util.logging.Level;
import java.util.logging.Logger;
public class Programmersx {
public static void main(String[] args) throws IOException {
StudentsMarks myObject = new StudentsMarks();
StudentsMarks myObject1 = new StudentsMarks();
StudentsMarks myObject2 = new StudentsMarks();
System.out.print("Please enter your student Name : ");
Scanner myObj = new Scanner(System.in); // Create a Scanner object
myObject.setStudentName(myObj.next()) ;
System.out.print("Please enter your student Id : ");
myObject.setStudentId(myObj.nextInt()) ;
System.out.println("Please enter your marks of 5 courses : ");
double marks[] = new double [5];
for (int i = 0; i < 5; i++) {
marks[i]= myObj.nextInt();
}
myObject.setMarks(marks) ;
System.out.print("Please enter your student Name : ");
Scanner myObj1 = new Scanner(System.in); // Create a Scanner object
myObject1.setStudentName(myObj1.next()) ;
System.out.print("Please enter your student Id : ");
myObject1.setStudentId(myObj1.nextInt()) ;
System.out.println("Please enter your marks of 5 courses : ");
double marks1[] = new double [5];
for (int i = 0; i < 5; i++) {
marks1[i]= myObj1.nextInt();
}
myObject1.setMarks(marks) ;
myObject1.toString();
System.out.print("Please enter your student Name : ");
Scanner myObj2 = new Scanner(System.in); // Create a Scanner object
myObject2.setStudentName(myObj2.next()) ;
System.out.print("Please enter your student Id : ");
myObject2.setStudentId(myObj2.nextInt()) ;
System.out.println("Please enter your marks of 5 courses : ");
double marks2[] = new double [5];
for (int i = 0; i < 5; i++) {
marks2[i]= myObj2.nextInt();
}
myObject2.setMarks(marks) ;
myObject2.toString();
myObject.toString();
myObject.toFile("Reem.txt");
myObject1.toFile("MAria.txt");
myObject2.toFile("Abrar.txt");
System.out.println("display the count of the instantiated objects from StudentMarks: " + StudentsMarks.NoInstntitd );
}
}
输出为
运行:
Please enter your student Name : jack
Please enter your student Id : 1123
Please enter your marks of 5 courses :
6
4
5
7
6
Please enter your student Name : mick
Please enter your student Id : 87534
Please enter your marks of 5 courses :
6
4
3
22
5
Please enter your student Name : meno
Please enter your student Id : 43433
Please enter your marks of 5 courses :
6
55
33
22
7
student information :jack1123 average 5.6
student average. : 5.6
2019/12/06
student information :mick87534 average 5.6
student average. : 5.6
2019/12/06
student information :meno43433 average 5.6
student average. : 5.6
2019/12/06
display the count of the instantiated objects from StudentMarks: 6
最佳答案
所有 StudentMarks 对象都通过类似的调用设置其标记:
myObject2.setMarks(marks)
它们都使用相同的标记数组，因此它们都具有相同的标记。
即使您更改了标记数组的内容
myObject.setMarks(marks)
和
myObject1.setMarks(marks)
仍然只有一个标记数组，由所有 StudentMarks 对象共享:StudentMarks setter 不复制该数组。
关于java - 为什么java方法返回相同的结果？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/59205638/