Heap corruption detected: after normal block (#153) at 0x00345730

#ifndef COW_H__
#define COW_H__
 
 
class Cow
{
    char name[20];
    char *hobby;
    double weight;
    static int num;// chislo obektov
public:
    Cow();
    Cow(const char * nm, const char *ho, double wt);
    Cow(const Cow & c);
    ~Cow();
    Cow & operator=(const Cow & c);
    void ShowCow() const;
    static int HowMany();
};
#endif

#include <iostream>
using namespace std;
#include "cow.h"
#include <cstring>
 
 
int Cow::num = 0;
int Cow::HowMany()
{
    return num;
}
Cow::Cow() //konstruktor po ymolchaniu
{
    cout << "Objekt num sozdan " << num++ << endl;
    name[0] = '\0';
    hobby = 0;
    weight = 0.0;
}
 
Cow::Cow(const char * nm, const char *ho, double wt)// konstruktor
{
    cout << "Objekt num sozdan " << num++ << endl;
    strcpy(name, nm);
    hobby = new char[strlen(ho + 1)];
    strcpy(hobby, ho);
    weight = wt;
    
}
 
Cow::~Cow()// destruktir
{
    cout << "Objekt num udalen " << --num << endl;
    delete [] hobby;
}
 
Cow & Cow::operator=(const Cow & c)// function prisvaivaniya
{       
    if (this == &c)
        return *this;
    strcpy(name, c.name);
    delete [] hobby;
    hobby = new char[strlen(c.hobby + 1)];
    strcpy(hobby, c.hobby);     
    return *this;
}
 
void Cow::ShowCow() const
{
    cout << "name " << name << endl;
    cout << "hobby " << hobby << endl;
    cout << "weight " << weight << endl;
}
 
Cow::Cow(const Cow & c)//konstruktor copyrovaniya
{
    cout << "Objekt num sozdan " << num++ << endl;
    strcpy(name, c.name);
    hobby = new char[strlen(c.hobby + 1)];
    strcpy(hobby, c.hobby);
    weight = c.weight;  
}

#include "cow.h"
#include <iostream>
using namespace std;
 
int main()
{
    Cow rosa("Redrose", "Whiterose", 777.7);
    rosa.ShowCow();
    Cow pion("Redpion", "Whitepion", 7.0);
    pion.ShowCow();
    pion = rosa;
    pion.ShowCow();
    Cow gvozdika = pion;
    gvozdika.ShowCow();
    cout << "Programma ispolsovala " << Cow::HowMany() << " obectov Cow " << endl;
    return 0;
}

 hobby = new char[strlen(c.hobby + 1)];

 hobby = new char[strlen(c.hobby)+ 1];