C++ Book program with classes

i got this program the other day and ive just started it and i am getting some errors that i cant figure out.

requirements: 1)create a clas called Book. a Book has three data members: m_title, m_id and m_flag to tell whether the book is in or checked out. 2)Write a constructor for Book. write a constructor that takes 3 parameters: Book(char * title, int id, bool flag) and initializes the 3 data members accordingly. in addition print out a message inside your constructor whenever it gets called. 3) Instantiate or create a few Book objects to test your constructor in main()-notice when your constructor is called. Book book1("Petzlod" , 100, false);
Book book2("Nagler", 101, true);
Book book3("Meyers", 102, false);
this is where im stuck at. heres the code:

// file: book.h
// CST 136
// Class definition for book class


#ifndef BOOK_H
#define BOOK_H


class Book{

private:
char m_title;
int m_id;
bool m_flag;

public:

Book();
Book(char * title, int id, bool flag); // 3 argument constructor


}

#endif

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// file: book.cpp
// CST 136
// code for the member functions of class Book

#include <iostream>
using std::cout;
using std::cin;
using std::endl;

#include "book.h"


Book::Book()
{

}

Book::Book(char * title, int id, bool flag)
{
char * m_title = title;
int m_id = id;
bool m_flag = flag;
}

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main.cpp

#include <iostream>
using std::cout;
using std::cin;
using std::endl;

#include "book.h"

void main()
{
Book book1("Petzlod" , 100, false);
Book book2("Nagler", 101, true);
Book book3("Meyers", 102, false);


}

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heres the errors: 1)'Book::{ctor} ' : constructors not allowed a return type
2)'Book' followed by 'void' is illegal (did you forget a ';'?)
3)return type of 'main' should be 'int' instead of 'Book'

any help will work and be appreciated. thanks