How can get the key of value in arraylist?

Question

I have a teacher class
Teacher has name and code.
Arraylist<Teacher> teachers;
Teacher t = new Teacher();
t.add(“teacher1”, 100);
teachers.add(t);
String name =teachers.get(teachers.IndexOf(100)).getName();
//this do not return name of teacher. Why??

Answer 1

think we have more than one teacher inside arraylist, and want get the name of a teacher with code, mean we have code and we need name, how can get that??
teachers[“rashban” 100, “hamid” 101]
we have 100, how can get rashban without for?

Answer 2

import java.util.ArrayList;

class Test
{
public static void main(String args[])
{
Teacher t1 = new Teacher("Rishabh", 100);
Teacher t2 = new Teacher("Hamid",101);
ArrayList<Teacher> teacher = new ArrayList<Teacher>();
teacher.add(t1);
teacher.add(t2);
System.out.println(t1.getNameByCode(100));
System.out.println(t2.getNameByCode(101));

}
}

public class Teacher {
private String name;
private int code;

public String getName()
{
return this.name;
}
public int getCode()
{
return this.code;
}
public Teacher(String name, int code)
{
this.name= name;
this.code=code;
}
public String getNameByCode(int code)
{
return this.name;
}
}

Answer 3

Where is your Teacher class??

Answer 4

public class Teacher {
private String name;
private int code;

public String getName()
{
return this.name;
}
public int getCode()
{
return this.code;
}
public Teacher(String name, int code)
{
this.name= name;
this.code=code;
}
}

class Test
{
public static void main(String args[])
{
Teacher t1 = new Teacher("Rishabh", 100);
ArrayList<Teacher> teacher = new ArrayList<Teacher>();
teacher.add(t1);
System.out.println(t1.getName());
System.out.println(t1.getCode());

}
}

// You can do this. Thanks for posting this question :-)

Answer 5

public class Teacher{
private String name;
int code;

public Teacher(){

}

//with getter and setter for name and code.
}

Answer 6

think we have more than one teacher in arraylist, how can get the name of a teacher when we have its code?