C++Primer Plus（第六版） 第十二章 第一题

本题主要是对本章基本内容的掌握，对于动态分配内存（new、new[]）的情况下析构函数要对应用delete、delete[]，同时由于析构函数只有一个，故注意所有的构造函数（包括重载的=运算符等）都采用相同的动态内存分配方式。

代码如下：

#include <iostream>
#include "cow.h"

Cow::Cow()
{
	hobby = new char[1];
	hobby[0] = '\0';
}

Cow::Cow(const char * nm, const char * ho, double wt)
{
	strcpy(name, nm);
	hobby = new char[strlen(ho) + 1];
	strcpy(hobby, ho);
	weight = wt;
}

Cow::Cow(const Cow & c)
{
	strcpy(name, c.name);
	hobby = new char[strlen(c.hobby) + 1];
	strcpy(hobby, c.hobby);
	weight = c.weight;
}

Cow::~Cow()
{
	delete[] hobby;
}

Cow & Cow::operator=(const Cow & c)
{
	if (this == &c)
		return *this;
	strcpy(name, c.name);
	delete[] hobby;
	hobby = new char[strlen(c.hobby) + 1];
	strcpy(hobby, c.hobby);
	weight = c.weight;
	return *this;
}

void Cow::showCow() const
{
	using std::cout;
	using std::endl;
	cout << "name: " << name << endl;
	cout << "hobby: " << hobby << endl;
	cout << "weight: " << weight << endl;
}

测试代码：

#include <iostream>
#include "cow.h"
using namespace std;
int main()
{
	{
		Cow cow();
	}
	Cow cow("abcd", "habby", 45);
	Cow adc = cow;
	cow.showCow();
	adc.showCow();
	cin.get();
	return 0;
}