【C++ Primer Plus习题】12.1

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问题:

解答:
main.cpp

#include <iostream>
#include "Cow.h"
using namespace std;int main()
{Cow c1;Cow c2("老母牛", "喝奶", 200);Cow c3(c2);c1 = c3;c1.ShowCow();cout << endl;c2.ShowCow();cout << endl;c3.ShowCow();cout << endl;return 0;
}

Cow.h

#pragma once
#include <iostream>
using namespace std;
class Cow
{char name[20];char* hobby;double weight;public:Cow();Cow(const char*nm,const char*ho,double wt);Cow(const Cow &c);~Cow();Cow& operator=(const Cow& c);void ShowCow()const;
};

Cow.cpp

#include "Cow.h"Cow::Cow()
{name[0] = '\0';hobby = NULL;weight = 0;
}
Cow::Cow(const char* nm, const char* ho, double wt)
{if ((strcpy_s(name, 20, nm)))cout << "复制失败原字符太长!" << endl;hobby = new char[strlen(ho)+1];strcpy_s(hobby, strlen(ho) + 1, ho);weight = wt;
}
Cow::Cow(const Cow&c)
{strcpy_s(name,20, c.name);hobby = new char[strlen(c.hobby) + 1];strcpy_s(hobby, strlen(c.hobby) + 1, c.hobby);weight = c.weight;
}
Cow::~Cow()
{delete[] hobby;
}
Cow& Cow::operator=(const Cow& c)
{if (this == &c){return *this;}if (hobby)delete[] hobby;strcpy_s(name, 20, c.name);hobby = new char[strlen(c.hobby) + 1];strcpy_s(hobby, strlen(c.hobby) + 1, c.hobby);weight = c.weight;return *this;
}
void Cow::ShowCow()const
{if (hobby == NULL){cout << "母牛的信息为空!" << endl;return;}cout << "母牛的名字为:" << name << endl;cout << "母牛的嗜好为:" << hobby << endl;cout << "母牛的体重为:" << weight << endl;
}