4elist1718.cpp

来自「《21天学通C＋＋》附盘的原代码。书上的每个例子在这里都有相应的C语言程序。」· C++ 代码 · 共 61 行

//Listing 17.18 Writing a Class to a File
#include <fstream>
#include <iostream.h>
using namespace std;

class Animal
{
public:
	Animal(int weight,long days):itsWeight(weight),DaysAlive(days){}
	~Animal(){}

	int GetWeight()const { return itsWeight; }
	void SetWeight(int weight) { itsWeight = weight; }

	long GetDaysAlive()const { return DaysAlive; }
	void SetDaysAlive(long days) { DaysAlive = days; }

private:
	int itsWeight;
	long DaysAlive;
};

int main()   // returns 1 on error
{
	char fileName[80];


	cout << "Please enter the file name: ";
	cin >> fileName;
	ofstream fout(fileName,ios::binary);
	if (!fout)
	{
		cout << "Unable to open " << fileName << " for writing.\n";
		return(1);
	}

	Animal Bear(50,100);
	fout.write((char*) &Bear,sizeof Bear);

	fout.close();

	ifstream fin(fileName,ios::binary);
	if (!fin)
	{
		cout << "Unable to open " << fileName << " for reading.\n";
		return(1);
	}

	Animal BearTwo(1,1);

	cout << "BearTwo weight: " << BearTwo.GetWeight() << endl;
	cout << "BearTwo days: " << BearTwo.GetDaysAlive() << endl;

	fin.read((char*) &BearTwo, sizeof BearTwo);

	cout << "BearTwo weight: " << BearTwo.GetWeight() << endl;
	cout << "BearTwo days: " << BearTwo.GetDaysAlive() << endl;
	fin.close();
	return 0;
}