Java 我试图得到某个学生的平均值，但它将所有值相加
我试图得到某个学生的平均值，但它将所有值相加。这是输出程序 CMPE 325 Student Record Holder System -------------------------------- 1.Add Student 2.View Records 3.Update Students 4.Get Average 5.Exit -------------------------------- Enter your choice: 1 How many Students you want to input?: 2 Student[1]Enter Id Number: 1 First Name: Erwin Middle Name: asdasdas Last Name: sadasdas Degree: asdasdas Year Level: 1 Student[2]Enter Id Number: 2 First Name: INK Middle Name: asdasd Last Name: asdas Degree: sadas Year Level: 3 CMPE 325 Student Record Holder System -------------------------------- 1.Add Student 2.View Records 3.Update Students 4.Get Average 5.Exit -------------------------------- Enter your choice: 3 Enter Id Number: 1 ----------------Student Info-------------- Id Number: 1 Name:Erwin asdasdas sadasdas Degree and Year: asdasdas-1 The number of Subjects: 3 Name of Course: Law Enter Grade: 3 Name of Course: Laww2 Enter Grade: 1 Name of Course: Law4 Enter Grade: 2 Enter another subject and grade? [Y]or[N]n CMPE 325 Student Record Holder System -------------------------------- 1.Add Student 2.View Records 3.Update Students 4.Get Average 5.Exit ------------------------------- Enter your choice: 3 Enter Id Number: 2 ----------------Student Info-------------- Id Number: 2 Name:IDK asdasd asdas Degree and Year: sadas-3 The number of Subjects: 2 Name of Course: psych Enter Grade: 3 Name of Course: egg Enter Grade: 2 Enter another subject and grade? [Y]or[N]n CMPE 325 Student Record Holder System -------------------------------- 1.Add Student 2.View Records 3.Update Students 4.Get Average 5.Exit -------------------------------- Enter your choice: 4 ENTER ID NUMBER: 1 SUM: 11.0 AVERAGE: 2.2 学生记事 公共类Rec { 私有字符串IDNumber； 私有字符串名； 私有字符串名称； 私有字符串lastName； 私有字符串度； 私营部门一级Java 我试图得到某个学生的平均值，但它将所有值相加,java,arraylist,Java,Arraylist,我试图得到某个学生的平均值，但它将所有值相加。这是输出程序 CMPE 325 Student Record Holder System -------------------------------- 1.Add Student 2.View Records 3.Update Students 4.Get Average 5.Exit -------------------------------
@Override
public String toString()
{
return ("ID Number: "+this.getIdNumber()+
"\nName: "+ this.getFirstName()+
" "+ this.getMiddleName()+
" "+ this.getLastName()+
"\nDegree and YearLevel: "+ this.getDegree() +
" - " + this.getYearLevel());
}
public Rec()
{
String IDNum;
String fName;
String mName;
String lName;
String deg;
int level;
}
public Rec(String IDNum, String fName, String mName, String lName, String deg,int level )
{
this.IDNumber=IDNum;
this.firstName=fName;
this.middleName=mName;
this.lastName=lName;
this.degree=deg;
this.yearLevel=level;
}
public void setIdNumber(String IDNumber)
{
this.IDNumber = IDNumber;
}
public void setFirstName(String firstName)
{
this.firstName=firstName;
}
public void setMiddleName(String middleName)
{
this.middleName=middleName;
}
public void setLastName(String lastName)
{
this.lastName=lastName;
}
public void setDegree(String degree)
{
this.degree=degree;
}
public void setYearLevel(int yearLevel)
{
this.yearLevel=yearLevel;
}
public String getIdNumber()
{
return IDNumber;
}
public String getFirstName()
{
return firstName;
}
public String getMiddleName()
{
return middleName;
}
public String getLastName()
{
return lastName;
}
public String getDegree()
{
return degree;
}
public int getYearLevel()
{
return yearLevel;
}
}
你不应该在把所有的东西都加到总数之后再计算平均数吗？ 您应该计算for循环外的平均值
for(int ind=0;ind<records.size();ind++)
{
sum += records.get(ind).getGrade();
}
average=sum/records.size();
System.out.println(average);
平均值需要在整个for循环相加后计算，就像Prasad之前所说的那样。您需要发布整个代码，以便我们了解结构。如何维护“记录”以及所有内容 有了可用的代码，我的理解是：
if(ID.equals(record.get(xx).getIdNumber()))
for(int ind=0;ind<records.size();ind++)
{
sum += records.get(ind).getGrade();
average=sum/records.size();
}
也许你可以试试这个：
ID = in.nextLine();
for (int ind = 0; ind < records.size(); ind++) {
if (ID.equals(record.get(ind).getIdNumber())) {
sum += records.get(ind).getGrade();
}
}
System.out.print("SUM: " + sum);
average = sum / records.size();
System.out.print("\nAVERAGE: " + average);
对不起，格式不对。：输入是什么，输出是什么，请举例说明？@user3145523为什么要撤消我的编辑？我更正了显示，使您的问题清晰明了…@atk对您的帖子进行了很好的编辑，为什么要将其还原？对不起，我现在正在还原ryt它仍在添加所有内容grades@SrinathGanesh你是说想要？我还是不能明白了。@SrinathGanesh你介意帮我吗？即使我把它搬出去了，它还是会增加所有的东西loop@SrinathGanesh我现在还原了代码。。我仍然坚持使用此代码。@user3145523上面的代码就是我的意思，我刚刚发布了格式，多亏了snocavotia，他给了你全部信息code@snocovatiaforint ind=0；indNo，这是一个典型的0刷新您的browser.我在发布后5秒编辑了它。它仍然添加了输入的整数，records.size正在计算为1。试着打印出来。这就是为什么。这值得更多的投票。感谢Srinath的努力。这肯定是所有答案中最重要的。很好。很抱歉，我没有在上面发布我的全部代码，我坚持格式。它说我必须添加更多评论我现在把我的代码贴在上面，我会试试，然后返回you@user3145523请看最后一部分post@SrinathGanesh好的，我去
深入了解更多参考资料和其他备选方案非常感谢：我现在已经发布了全部代码。我很抱歉回复晚了，我正在试验我的整个程序
for(int ind=0;ind<records.size();ind++)
{
sum += records.get(ind).getGrade();
average=sum/records.size();
}
String ID = "fillit";
// fetch grade list
for(ArrayList gradeList2 : records.get(ID).grade)
{
double sum = 0.0;
double average = 0.0;
// cal values for all grades
for(int gradeValue : gradeList2)
{
sum = sum + gradeValue;
}
// cal average of sum
average = sum / gradeList2.count();
}
System.out.print("SUM: "+sum);
System.out.print("\nAVERAGE: "+average);
import java.util.ArrayList;
import java.util.Scanner;
public class RecHolder {
static ArrayList<Rec> record = new ArrayList<Rec>();
static ArrayList<Grade> records = new ArrayList<Grade>();
public RecHolder() {
menu();
}
@SuppressWarnings("resource")
public static void menu() {
Scanner in = new Scanner(System.in);
int choice;
System.out.println("CMPE 325 Student Record Holder System");
System.out.println("--------------------------------");
System.out.println("1.Add Student");
System.out.println("2.View Records");
System.out.println("3.Update Students");
System.out.println("4.Get Average");
System.out.println("5.Exit");
System.out.println();
System.out.println("--------------------------------");
System.out.print("Enter your choice: ");
choice = in.nextInt();
switch (choice) {
case 1:
record();
break;
case 2:
display();
break;
case 3:
update();
break;
case 4:
average();
break;
case 5:
break;
}
}
public static void record() {
Scanner in = new Scanner(System.in);
int total;
System.out.println("How many Students you want to input?: ");
total = in.nextInt();
Rec[] student = new Rec[total];
for (int index = 0; index < student.length; index++) {
student[index] = new Rec();
System.out.printf("Student[%d]", index + 1);
System.out.println("Enter");
in.nextLine();
System.out.print("Id Number: ");
student[index].setIdNumber(in.nextLine());
System.out.print("First Name: ");
student[index].setFirstName(in.nextLine());
System.out.print("Middle Name: ");
student[index].setMiddleName(in.nextLine());
System.out.print("Last Name: ");
student[index].setLastName(in.nextLine());
System.out.print("Degree: ");
student[index].setDegree(in.nextLine());
System.out.print("Year Level: ");
student[index].setYearLevel(in.nextInt());
record.add(student[index]);
}
menu();
}
public static void displayall() {
Scanner in = new Scanner(System.in);
if (record.size() == 0) {
System.out.print("Invalid\n");
in.nextLine();
menu();
} else {
if (records.size() == 1) {
System.out
.print("-------------The Record for all Student-----------");
for (int i = 0; i < record.size(); i++) {
System.out.printf("\nStudent[%d]", i + 1);
System.out.print("\nId Number: "
+ record.get(i).getIdNumber());
System.out.print("\nName: " + record.get(i).getFirstName()
+ " " + record.get(i).getMiddleName() + " "
+ record.get(i).getLastName());
System.out.print("\nDegree and Year: "
+ record.get(i).getDegree() + "-"
+ record.get(i).getYearLevel() + "\n\n");
}
in.nextLine();
display();
}
else {
System.out
.print("--------------The Record for all Student------------");
for (int i = 0; i < record.size(); i++) {
System.out.printf("\nStudent[%d]", i + 1);
System.out.print("\nId Number: "
+ record.get(i).getIdNumber());
System.out.print("\nName: " + record.get(i).getFirstName()
+ " " + record.get(i).getMiddleName() + " "
+ record.get(i).getLastName());
System.out.print("\nDegree and Year: "
+ record.get(i).getDegree() + "-"
+ record.get(i).getYearLevel() + "\n\n");
}
// for(int loopforSubjct = 0 ; loopforSubjct < records.size();
// loopforSubjct++ )
// {
// System.out.printf("\nSubject: "+
// records.get(loopforSubjct).getSubject()+" Grade: "+
// records.get(loopforSubjct).getGrade());
// }
in.nextLine();
}
}
display();
}
public static void specific() {
Scanner in = new Scanner(System.in);
if (record.size() == 0) {
System.out.print("Enter Data 1st\n");
in.nextLine();
menu();
} else {
String id = new String();
System.out.print("Enter Id Number: ");
id = in.nextLine();
if (records.size() == 1) {
for (int loopforSpcfc = 0; loopforSpcfc < record.size(); loopforSpcfc++) {
if (id.equals(record.get(loopforSpcfc).getIdNumber())) {
System.out
.printf("\n ----------------Student Exists-------------- ");
System.out.print("\nId Number: "
+ record.get(loopforSpcfc).getIdNumber());
System.out.print("\nName:"
+ record.get(loopforSpcfc).getFirstName() + " "
+ record.get(loopforSpcfc).getMiddleName()
+ " " + record.get(loopforSpcfc).getLastName());
System.out.print("\nDegree and Year: "
+ record.get(loopforSpcfc).getDegree() + "-"
+ record.get(loopforSpcfc).getYearLevel()
+ "\n\n");
in.nextLine();
} else {
in.nextLine();
System.out.print("Student Number Invalid!\n");
menu();
}
}
}
else {
for (int loopforSpcfc = 0; loopforSpcfc < record.size(); loopforSpcfc++) {
if (id.equals(record.get(loopforSpcfc).getIdNumber())) {
System.out.printf("\nStudent Exists");
System.out.print("\nId Number: "
+ record.get(loopforSpcfc).getIdNumber());
System.out.print("\nName: "
+ record.get(loopforSpcfc).getFirstName() + " "
+ record.get(loopforSpcfc).getMiddleName()
+ " " + record.get(loopforSpcfc).getLastName());
System.out.print("\nDegree and Year: "
+ record.get(loopforSpcfc).getDegree() + "-"
+ record.get(loopforSpcfc).getYearLevel()
+ "\n\n");
System.out.println();
}
}
for (int loopforSubjct = 0; loopforSubjct < records.size(); loopforSubjct++) {
System.out.printf("\nSubject: "
+ records.get(loopforSubjct).getSubject()
+ " Grade: "
+ records.get(loopforSubjct).getGrade());
}
in.nextLine();
}
}
display();
}
public static void update() {
Scanner in = new Scanner(System.in);
if (record.size() == 0) {
System.out.print("Enter Data 1st\n");
in.nextLine();
menu();
} else {
String idnum = new String();
char answer;
in.nextLine();
System.out.print("Enter Id Number: ");
idnum = in.nextLine();
int total;
for (int loopforSpcfc = 0; loopforSpcfc < record.size(); loopforSpcfc++) {
if (idnum.equals(record.get(loopforSpcfc).getIdNumber())) {
System.out
.printf("\n ----------------Student Info-------------- ");
System.out.print("\nId Number: "
+ record.get(loopforSpcfc).getIdNumber());
System.out.print("\nName:"
+ record.get(loopforSpcfc).getFirstName() + " "
+ record.get(loopforSpcfc).getMiddleName() + " "
+ record.get(loopforSpcfc).getLastName());
System.out.print("\nDegree and Year: "
+ record.get(loopforSpcfc).getDegree() + "-"
+ record.get(loopforSpcfc).getYearLevel() + "\n\n");
in.nextLine();
}
}
for (int loop = 0; loop < record.size(); loop++) {
{
if (idnum.equals(record.get(loop).getIdNumber())) {
System.out.println("The number of Sujects: ");
total = in.nextInt();
do {
Grade[] update = new Grade[total];
for (int indexupdater = 0; indexupdater < update.length; indexupdater++) {
update[indexupdater] = new Grade();
// set ID... String
update[indexupdater].setIDNumber(idnum);
in.nextLine();
System.out.print("Name of Course: ");
update[indexupdater].setSubject(in.nextLine());
System.out.print("Enter Grade: ");
update[indexupdater].setGrade(in.nextDouble());
records.add(update[indexupdater]);
}
System.out
.print("Enter another subject and grade? [Y]or[N]");
String ans = in.next();
answer = ans.charAt(0);
} while (answer == 'y');
}
}
}
}
menu();
}
public static void average() {
Scanner in = new Scanner(System.in);
if (record.size() == 0) {
System.out.print("Enter Data 1st\n");
in.nextLine();
menu();
} else {
double sum = 0;
double average = 0;
String ID = new String();
System.out.print("Enter An Valid Id Number: ");
ID = in.nextLine();
for (Rec rec : record) {
if (rec.getIdNumber().equals(ID)) {
for (Grade grade : records) {
if (grade.getIDNumber().equals(ID)) {
// System.out.println(grade.getIDNumber());
sum = sum + grade.getGrade();
}
} // end loop-grade
average = sum / records.size();
} // end if
} // end loop-rec
System.out.print("SUM: " + sum);
System.out.print("\nAVERAGE: " + average);
}
}
public static void display() {
Scanner input = new Scanner(System.in);
int choice;
System.out.println("--------------------------------");
System.out.println("1.View List");
System.out.println("2.View Specific Record");
System.out.println("3.Exit");
System.out.println();
System.out.println("--------------------------------");
System.out.print("Enter your choice: ");
choice = input.nextInt();
switch (choice) {
case 1:
displayall();
break;
case 2:
specific();
break;
case 3:
menu();
break;
}
}
public static void main(String[] args) {
new RecHolder();
}
}
class Grade {
private String IDNumber;
private String subject;
private double grade;
private double average;
public Grade() {
String IDNum;
String sub;
double grad;
double ave;
}
public Grade(String IDNum, String sub, double grad, double ave) {
this.IDNumber = IDNum;
this.subject = sub;
this.grade = grad;
this.average = ave;
}
public void setSubject(String subject) {
this.subject = subject;
}
public String getSubject() {
return subject;
}
public void setGrade(double grade) {
this.grade = grade;
}
public double getGrade() {
return grade;
}
public String getIDNumber() {
return IDNumber;
}
public void setIDNumber(String ID) {
this.IDNumber = ID;
}
}
public class Rec {
private String IDNumber;
private String firstName;
private String middleName;
private String lastName;
private String degree;
private int yearLevel;
@Override
public String toString() {
return ("ID Number: " + this.getIdNumber() + "\nName: "
+ this.getFirstName() + " " + this.getMiddleName() + " "
+ this.getLastName() + "\nDegree and YearLevel: "
+ this.getDegree() + " - " + this.getYearLevel());
}
public Rec() {
String IDNum;
String fName;
String mName;
String lName;
String deg;
int level;
}
public Rec(String IDNum, String fName, String mName, String lName,
String deg, int level) {
this.IDNumber = IDNum;
this.firstName = fName;
this.middleName = mName;
this.lastName = lName;
this.degree = deg;
this.yearLevel = level;
}
public void setIdNumber(String IDNumber) {
this.IDNumber = IDNumber;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public void setMiddleName(String middleName) {
this.middleName = middleName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public void setDegree(String degree) {
this.degree = degree;
}
public void setYearLevel(int yearLevel) {
this.yearLevel = yearLevel;
}
public String getIdNumber() {
return IDNumber;
}
public String getFirstName() {
return firstName;
}
public String getMiddleName() {
return middleName;
}
public String getLastName() {
return lastName;
}
public String getDegree() {
return degree;
}
public int getYearLevel() {
return yearLevel;
}
}
ID = in.nextLine();
for (int ind = 0; ind < records.size(); ind++) {
if (ID.equals(record.get(ind).getIdNumber())) {
sum += records.get(ind).getGrade();
}
}
System.out.print("SUM: " + sum);
average = sum / records.size();
System.out.print("\nAVERAGE: " + average);