Thread: logical error in output

Hello there,

I have wrote the below code and its working perfectly,when i tried to add a static field (noOfPerson) to show me the number of persons that is created in the main class, i get a wrong number !
I would really appreciate it if you review my code for any error.

public class Person {
 private int age;
 private String name;
 private static int noOfPerson = 0;
 
  public Person(String a_name, int a_age){
     setName(a_name);
     setAge(a_age);
     setNoOfPerson();}
 public Person(){
    this("None", 1);
    setNoOfPerson();
 
 }
 public Person(String a_name){
     this(a_name, 1);
     setNoOfPerson();
 }
 public Person(int a_age){
     this("None",a_age);
      setNoOfPerson();
 }
 
 
 
 public void setName(String a_name){
     name = a_name;
 }
public String getName(){ return name;}
 
public void setAge(int a_age){
    age = a_age;
 
}
 public int getAge(){ return age;}
 public static void  setNoOfPerson(){
     Person.noOfPerson++;
 }
 public static int getNoOfPerson(){ return noOfPerson;}
 
 public String toString() {
   return String.format("%s is %d years old.", getName(), getAge());
 }
 
 }

class including main method

public class Person_Test {
    public static void main (String[] args){
        Person employ1 = new Person("Ahmad", 32);
        System.out.println(employ1.toString());
        Person employ2 = new Person("Ali");
        System.out.println(employ2.toString());
        Person employ3 = new Person(28);
        System.out.println(employ3.toString());
        Person employ4 = new Person();
        System.out.println(employ4.toString());
        System.out.println(Person.getNoOfPerson());
    }
}

here at the end its suppose to show me (Person.getNoOfPerson()) number 4 but im getting number 7!


Thanks in advance for your help.
Best Regards,

Your constructors are calling each other and all of them increment noOfPerson. Only call setNoOfPerson from Person(String a_name, int a_age) as every other constructor calls this constructor.