11_97.cpp

a programme set to teach you how to use c

#include<iostream.h>
#include<fstream.h>
#include<iomanip.h>
static int n=0;
int comp(char*,char*);
class MyFriend
{
	char tag;
	unsigned int age;
	char name[12];
	char TelNo[12];
public:
	int getMyFriendNo(){return age;}
	void getdata()
	{
		tag='#';
		cout<<"(年龄 姓名 电话):";
		cin>>age>>name>>TelNo;
	}
	char gettag(){return tag;}
	void disp()
	{
		if(tag=='#')
		cout<<setiosflags(ios::left)
		 <<setw(6)<<age<<setw(10)<<name<<setw(7)<<TelNo<<endl;
	}
	char *getname()
	{
		return name;
	}
};
void func1()
{
	ofstream output("MyFrd.dat");
	MyFriend s;	
	cout<<"输入数据"<<endl;
	cout<<"我的朋友人数:";
	cin>>n;
	for(int i=0;i<n;i++)
	{
		cout<<"第"<<i+1<<"个我的朋友";
		s.getdata();
		output.write((char *)&s,sizeof(s));
	};
	output.close();
}
void func2()
{
	ifstream input("MyFrd.dat");
	MyFriend s;
	cout<<"输入数据:"<<endl;
	cout<<setiosflags(ios::left)
	<<setw(6)<<"年龄"<<setw(10)<<"姓名"<<setw(7)<<"电话"<<endl;
	input.read((char *)&s,sizeof(s));
	while(input)
	{
		s.disp();
		input.read((char*)&s,sizeof(s));
	};
	input.close();
}
void func3()
{
	char sname[10];
	ifstream file("MyFrd.dat");
	MyFriend one;
	file.seekg(0);
	cout<<"输入要查询的姓名（可只输入姓氏）:";
	cin>>sname;
	cout<<"输出查询结果:"<<endl;
	cout<<setw(6)<<"年龄"<<setw(10)<<"姓名"<<setw(6)<<"电话"<<endl;	
	file.read((char *)&one,sizeof(one));
	while(file)
	{
		if(comp(one.getname(),sname)==1)
			one.disp();
		file.read((char*)&one,sizeof(one));
	};
	file.close();
}
void func4()
{
	fstream outapp("MyFrd.dat",ios::app);
    MyFriend one;
	cout<<"添加数据:";
	one.getdata();
	outapp.write((char*)&one,sizeof(one));
	outapp.close();
}
void func5()
{
	char  sname[12] ;int i=0;
	fstream outdel("MyFrd.dat",ios::in|ios::out);
	MyFriend one;
	outdel.seekg(0);
	cout<<"输入要删除的姓名（可只输入姓氏）:";
	cin>>sname;
	while(!outdel.eof())
	{
		outdel.seekp(sizeof(MyFriend)*i);
        outdel.read((char *)&one,sizeof(one));
		if(comp(one.getname(),sname)==1 && one.gettag()=='#')
		{
			outdel.seekp(sizeof(MyFriend)*i);
			outdel.put('*');
		}
        i++;
	}
	outdel.close();
}
void func6()
{
	fstream outdel("MyFrd.dat",ios::in);
	fstream temp("temp",ios::out|ios::trunc);
    MyFriend s;
	while(!outdel.eof())
	{
		outdel.read((char *)&s,sizeof(MyFriend));
		if(s.gettag()=='#')
			temp.write((char *)&s,sizeof(MyFriend));
	}
	outdel.close();
	temp.close();
	fstream outdel1("MyFrd",ios::out|ios::trunc);
	fstream temp1("temp",ios::in);
	while(!temp1.eof())
	{
		temp1.read((char *)&s,sizeof(MyFriend));
		outdel1.write((char *)&s,sizeof(MyFriend));
	}
	outdel1.close();
	temp1.close();
	cout<<"此记录已物理删除"<<endl;
}
int comp(char s1[],char s2[])
{
	int i=0;
	while(s1[i]!='\0' && s2[i]!='\0' && s1[i]==s2[i])
		i++;
	if(s1[i]=='\0' || s2[i]=='\0')
		return 1;
    else
		return 0;
}
void main()
{
	int sel;
	do
	{
		cout<<"请选择（1:输入数据 2：输出数据 3:按姓名查询" <<endl
			<<"4:添加数据 5:逻辑删除 6:物理删除 其它退出）：";
		cin>>sel;
		switch(sel)
		{
       case 1:func1();break;
       case 2:func2();break;
		 case 3:func3();break;
		 case 4:func4();break;
		 case 5:func5();break;
		 case 6:func6();break;
		}
	}while(sel>=1 && sel<=6);
}