Static using object count

#include<iostream>
#include<string>
#include<stdlib.h>

using namespace std;

class Student{
private:
    static int countStd;
    char* idStr;
    int id;
    string dept;
public:
    Student(int id, string dept);
    string getId();
    int getObjectCount();
    ~Student();

};

int Student::countStd = 0;


Student::Student(int id, string dept){
this->id = id;
this->dept = dept;
idStr = new char[10];
cout<<"\ninside constructor - "<< ++countStd<<" th Object\n";

}
int Student::getObjectCount(){
return countStd;
}

string Student::getId(){
    itoa(this->id, idStr, 10);
return this->dept+"-" +string(idStr);
}

Student::~Student(){
cout<<"\ninside destructor\n";
countStd--;
delete [] idStr;
}

int main(){

Student student(1, "s1");
Student *s = new Student(2,"s2");
delete s;

cout<<"\nCurrent number of objects available: "<< s->getObjectCount();

return 0;
}