Trying to create a simple school system | Java Community | Help. Code. Learn. | Page 1

dusky socket Mar 22, 2023, 12:38 PM

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Hello guys. I'm trying to create a simple school system
It's a system that will receive only students and tests.
Students may have names and a kind of a list with test notes.
My system have to show the following options to the user:

Register student
List students
See biggest note.

E. Exit

If I choose the 2st option, the output will be something like this :

Carl
Jean
Peter

B. Back
E. Exit

If I choose 2 ( Jean ), I will have this :
Student : Jean
Tests Mean : 0
Biggest note : 0
Lower note : 0
Done tests : 0

Register test for this student

B. Back
E. Exit

If I choose 1 In order to register test, I have to ask the user the test note and register it .

I have done some things already but I'm facing some troubles :
-> My student class:

import java.util.ArrayList;

public class Student {
    private String name; // 1o nome do aluno
    private ArrayList<Tests> tests; //ArrayList de provas

    public Student(String name){
        this.name=name;
        tests = new ArrayList<Tests>();
    }

    public String getName() {
        return name;
    }

    public int testsNumber(){
        return tests.size();
    }

    public int testsMean(ArrayList tests){
        int sum=0;
        for(int d : tests){
            sum+= d;
        }
    }
}

And I want to create a System class, where the user will can do the options that I showed in the beginning.

But idk how to store the grades in the Student class. I created a ArrayList of Tests but how can I register those tests ? I need help with :
-> Adding a grade into my tests ArrayList
-> Returning the mean of my tests ArrayList
-> Return biggest and lowest grades
(This 3 topics inside Student class. Or not. Idk)

And, in system class :
-> Create a new Student
-> Show the options that I send in the top
-> Make the options work

Can someone help me ? I think it's simple but idk how to proceed. I will send the Test class inside help chat.

stoic barnBOT Mar 22, 2023, 12:38 PM

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dusky socket Mar 22, 2023, 12:38 PM

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This is my Test class.

import java.util.Scanner;

public class Tests {
    private int grade;

    public Tests(int grade){
        this.grade=grade;
    }

}

dense reef Mar 22, 2023, 2:03 PM

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dusky socket Hello guys. I'm trying to create a simple school system It's a system that will ...

Do you know about Scanner class?

dusky socket Mar 22, 2023, 2:14 PM

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Yep

dusky socket Mar 22, 2023, 2:14 PM

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dense reef Do you know about Scanner class?

I'm facing troubles in connecting those classes and dealing with the grades ArrayList

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import java.util.ArrayList;

public class Student {
    private String name; // 1o nome do aluno
    private int biggestGrade;
    private int lowestGrade;
    private int mean;
    private int doneTests;

    public Student(String name){
        this.name=name;
    }

    public String getName() {
        return name;
    }

    public void setName(String name){
    this.name= name}
}

#

I made some changes

#

import java.util.ArrayList;
import java.util.Scanner;

public class Tests {
    private ArrayList<Integer> grades ;

    public Tests(int grade){
        grades.add(grade);
    }
    public int testsMean(ArrayList tests){
        int sum = 0;

        for (int number : grades){
            sum += number;
        }

        int mean = sum/(grades.size());

        return mean;
    }


}

dense reef Mar 22, 2023, 2:18 PM

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dusky socket I'm facing troubles in connecting those classes and dealing with the grades Arra...

for example, when user chose Register test for this student, he should input a grade, right? So you read int from scanner and create a Test with that grade. And put that Test in the list of tests of a Student

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let's talk about this method: ```java
public int testsMean(ArrayList tests){
int sum = 0;

    for (int number : grades){
        sum += number;
    }

    int mean = sum/(grades.size());

    return mean;
}```

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you don't need to pass the tests arraylist, since class already contains the private ArrayList<Integer> grades ;

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imo, it should be like public int testsMean()

dusky socket Mar 22, 2023, 2:19 PM

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got it

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makes sense

dense reef Mar 22, 2023, 2:20 PM

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and, you need to add method that adds a grade to a test

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because constructor allows to take only one integer

dusky socket Mar 22, 2023, 2:20 PM

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I'm not doing this in my constructor ?

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Oh

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Got it

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So I have to call my constructor with no parameters and create a addGrade method, right ?

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And then add grades

dense reef Mar 22, 2023, 2:23 PM

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That sounds more right to me. But still I have some questions, like

why multiple grades for one test?
if one test - one grade, shouldn't you create different tests and put the grade as a value?
Because I don't really understand the structure you've chose to use

dusky socket Mar 22, 2023, 2:24 PM

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I agree with u, but idk how to implement this

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In my head creating a Tests class in order to store my grades and then retrieving those grades in my Student class makes sense

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But you're correct. It is one test-one grade relationship

dense reef Mar 22, 2023, 2:28 PM

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in that case you could implement it like:

student has list of Test, each test has grade and maybe a name of subject (for example, math)
when you need to find lowest - you run something like ```java
int lowestGrade() {
int lowest = 0;
for (Test test : testList) {
if (lowest > test.getGrade()) {
lowest = test.getGrade();
}
}
return lowest;
}

dusky socket Mar 22, 2023, 2:29 PM

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Following that way, I have to make any change in my Tests class ?

#

import java.util.ArrayList;
import java.util.Scanner;

public class Tests {
    private ArrayList<Integer> grades ;

    public Tests(int grade){
        grades.add(grade);
    }
    public int testsMean(){
        int sum = 0;

        for (int number : grades){
            sum += number;
        }

        int mean = sum/(grades.size());

        return mean;
    }


}

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That's it right now

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Woops

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Wrong code

dense reef Mar 22, 2023, 2:29 PM

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first if all, it should be called Test, not Tests, if you want to implement model "one test - one grade"

dusky socket Mar 22, 2023, 2:32 PM

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Better ?

dense reef Mar 22, 2023, 2:33 PM

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first of all, do we make one-to-one model, or one-to-many?

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one test one grade, or one test many grades

dusky socket Mar 22, 2023, 2:33 PM

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One test grade

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Then this method testsMean have to be inside students

dense reef Mar 22, 2023, 2:34 PM

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right

dusky socket Mar 22, 2023, 2:34 PM

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That's it ?

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So I have to create a ArrayList of Test in my Student Class ?

dense reef Mar 22, 2023, 2:35 PM

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right

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so Test could look like this:```java
class Test {
private int grade;

public Test(int grade) {
    this.grade = grade;
}

public int getGrade() {
    return grade;
}

}

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maybe in the future you will want to add name of test

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and relation to a subject

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up to you

dusky socket Mar 22, 2023, 2:36 PM

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got it

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how would be a method that add a Test ?

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Considering the relationship one test-one grade

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Because I can't use add method. The add wouldn't receive a grade, just another Test object

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I have to instantiate a new Test object and then pass a grade as a parameter ?

dense reef Mar 22, 2023, 2:43 PM

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right

dusky socket Mar 22, 2023, 2:56 PM

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import java.util.ArrayList;

public class Student {
    private String name; // 1o nome do aluno
    private int biggestGrade;
    private int lowestGrade;
    private int mean;
    private int doneTests;

    private ArrayList<Test> tests = new ArrayList<Test>();

    public Student(String name){
        this.name=name;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void addTest(int grade){
        Test newTest = new Test(grade);
        tests.add(newTest);
    }

    public int getLowestGrade(){
        int lowest = 0;
        for (Test test : tests) {
            if (lowest > test.getGrade()) {
                lowest = test.getGrade();
            }
        }
        return lowest;
    }

    public int getHighestGrade(){
        int highest = tests.indexOf(0);
        for (Test test : tests) {
            if (highest < test.getGrade()) {
                highest = test.getGrade();
            }
        }
        return highest;
    }
    public int testsMean(){
        int sum = 0;

        for (Test test : tests){
            sum += test.getGrade();
        }

        int mean = sum/(tests.size());

        return mean;
    }
}

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Does this makes sense ?

dense reef Mar 22, 2023, 3:01 PM

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yeah, nice

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maybe you should make testsMean as double, or round the mean

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I mean that making it int, it will return 2 if mean was 2.9, since int just ignores the value after point

dusky socket Mar 22, 2023, 3:04 PM

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got it

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i will try to implement the user options now in a System class

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Scanner is the correct type to use, right ?

dense reef Mar 22, 2023, 3:05 PM

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yeah

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~~I would do it static~~

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well, it depends

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anyways, make it as a field, not as a local object for each method

dense reef Mar 22, 2023, 3:14 PM

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dusky socket ```java import java.util.ArrayList; public class Student { private String n...

also, you don't need this field anymore: java private int biggestGrade; private int lowestGrade; private int mean; private int doneTests;

dusky socket Mar 22, 2023, 4:26 PM

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nice !

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I will finish it today

dusky socket Mar 22, 2023, 6:41 PM

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dense reef also, you don't need this field anymore: ```java private int biggestGrade; ...

do u still here ?

#Trying to create a simple school system