database.cpp

程序名称：学生管理信息管理系统 可以增加

#include"student.h"
#include<iostream.h>
#include<fstream.H>
#include<stdlib.h>
#include<iomanip.h>
#include<string.h>
#include<conio.h>

//a function that output using streams 
//(just the function "storeFile" needs it~~~ +_+
void outputLine(ostream&,Student&);
//make a new blank file
void makeNewFile();
//return a integar to compare with the enums
char  enterChoice();
//used to change the integar "choiceAfter" to 
//decide whether exit or continiue
char afterChoice();
//store data in a file called data.dat
void storeFile(fstream&);
//show a student's data according to the ID the user gives
void show(fstream&);
//add a new student according to the ID the user gives 
void add(fstream&);
//delete a student
void deleteStudent(fstream&);
//clean all the data in database
void cleanDatabase();
//display my information
void aboutMe();

int main()
{
    //the fstream object used to input and out from the file
	fstream inOutStream("data.dat",ios::in|ios::out);
	//check errors
   	if (!inOutStream)
	{
		cerr<<"File coule not be opened."<<endl;
		exit(1);
	}
    //used with enterChoice function to
	//judge the user'choice
	int choiceBefore;
	//judge the user'choice after the "choiceBefore"
	//to display"Press Y to continue or any other key to EXIT"
	char choiceAfter='y';
	while(choiceAfter=='y' && (choiceBefore=enterChoice())!='7')
	{
		switch(choiceBefore)
		{

		case '1':
			show(inOutStream);
			choiceAfter=afterChoice();
			break;
		case '2':
			add(inOutStream);
			choiceAfter=afterChoice();
			break;
		case '3':
			deleteStudent(inOutStream);
			choiceAfter=afterChoice();
			break;
		case '4':
			cleanDatabase();
			choiceAfter=afterChoice();
			break;
		case '5':
            aboutMe();
			choiceAfter=afterChoice();
			break;
		case '6':
			storeFile(inOutStream);
			choiceAfter=afterChoice();
			break;
		default:
			cerr<<"Incorrect choice\n";
			break;
		}
		
	inOutStream.clear();
	}
	return 0;
}

void makeNewFile()
{   
	ofstream outPut("data.dat");
	//check errors
	if(!outPut)
	{
		cerr<<"file cound not be opered."<<endl;
		exit(1);
	}
    //the blank data used to fill in the Data.dat
	Student blankStudent;
	//from 1~1000,fill the blank data into the file
	for(int i=0;i<1000;i++)
		outPut.write(reinterpret_cast<char*>(&blankStudent),
		sizeof(Student));
}

char  enterChoice()
{
	cout<<"                       WELCOME TO ALEX'S STUDENT DATABASE\n"
		<<"       *******************************************************************\n"
		<<"       **      *       *  Enter your choice              *       *      **\n"
		<<"       *  *      *     *  1--show an student             *     *      *  *\n"
  		<<"       *    *      *   *  2--add a new student           *   *      *    *\n"
		<<"       *      *      * *  3--delete a student            * *      *      *\n"
		<<"       * *      *      *  4--clean all data in database  *      *      * *\n"
		<<"       *   *      *    *  5--about me                    *    *      *   *\n"
		<<"       *     *      *  *  6--store data in print.txt     *  *      *     *\n"
		<<"       *       *      **  7--end program                 **      *       *\n"
		<<"       *******************************************************************\n"
		<<"?";

	char menuChoice;
	cin>>menuChoice;
	return menuChoice;
}
//used in the funtion "storeFile" to output in a formatted form
void outputLine(ostream &output,Student &tempStudent)
{
	output<<setiosflags(ios::left)
		<<setw(8)<<tempStudent.getId()
		<<setw(10)<<tempStudent.getLastName()
		<<setw(10)<<tempStudent.getFirstName()
		<<setw(7)<<tempStudent.getAge()
		<<setw(5)<<tempStudent.getScore()
		<<endl;
}

char afterChoice()
{
	char cAfter;
	cout<<"Press Y to continue or any other key to EXIT.\n";
	cin>>cAfter;
	if(cAfter=='y'||cAfter=='Y')
	cAfter='y';
	else
		cAfter='n';
	return cAfter;
}


void storeFile(fstream &readFromFile)
{
	//the file "print.txt" was connected to the 
	//stream class object storeFile
	ofstream storeFile("print.txt",ios::out);

	if(!storeFile)
	{
		cerr<<"File could not be opened."<<endl;
		exit(1);
	}
	
	storeFile<<setiosflags(ios::left)
		<<setw(8)<<"ID"
		<<setw(10)<<"LastName"
		<<setw(10)<<"FirstName"
		<<setw(7)<<"Age"
		<<setw(5)<<"Score"
		<<endl;
    //move the get file pointer to the begining of the "data.dat"
	readFromFile.seekg(0);
    
	Student student;
	readFromFile.read(reinterpret_cast<char*>(&student),
		sizeof(Student));
	while(!readFromFile.eof())
	{
		//the data will not be stored when the id is 0
		if((student.getId())!=0)
			outputLine(storeFile,student);

		readFromFile.read(reinterpret_cast<char*>(&student),
			sizeof(Student));
	}
	cout<<"The data has been stored in the file:print.txt.\n";
}

void show(fstream &showStudent)
{   
	Student student,student2;
	int id,idOfName;
	char firstName[10],lastName[10];

	cout<<"1-Show the student by id\n"
		<<"2-Show the student by name\n";

	int choice;
	cin>>choice;
	do
	{
		switch(choice)
		{
		case 1:
			//id that the user input to show 
			cout<<"Please input the student ID:\n(1~1000)?";
			cin>>id;
			//check the id,it must be a number between 1~1000
			do
			{
				if(id<1 || id>1000)
				{
					cout<<"Incorrect student ID";
					cout<<"\nPlease input the student ID:\n(1~1000)?";
					cin>>id;
				}
			}while(id<1 || id>1000);	
			
			showStudent.seekg((id-1)*sizeof(Student));
			showStudent.read(reinterpret_cast<char*>(&student)
				,sizeof(Student));
			if(student.getId()==0)
				cout<<"This ID is empty.\n";
			else
			{
				cout<<setiosflags(ios::left)
					<<setw(8)<<"ID"
					<<setw(15)<<"LastName"
					<<setw(15)<<"FirstName"
					<<setw(7)<<"Age"
					<<setw(5)<<"Score"
					<<endl;
				student.showData();
			}
			break;
		case 2:
			cout<<"Please input the first name\n:";
			cin>>firstName;
			cout<<"Please input the last name\n:";
			cin>>lastName;
			{
				for(int i=1;i<=1000;i++)
				{
					showStudent.seekg((i-1)*sizeof(Student));
					showStudent.read(reinterpret_cast<char*>(&student),
					sizeof(Student));
					if(!strcmp(student.getFirstName(),firstName)&&
					!strcmp(student.getLastName(),lastName))
					{
						showStudent.seekg((i-1)*sizeof(Student));
						showStudent.read(reinterpret_cast<char*>(&student2),
						sizeof(Student));
						idOfName=i;
						cout<<setiosflags(ios::left)
							<<setw(8)<<"ID"
							<<setw(15)<<"LastName"
							<<setw(15)<<"FirstName"
							<<setw(7)<<"Age"
							<<setw(5)<<"Score"<<endl;
						student2.showData();
					}
				}
				if(!strcmp(student2.getFirstName(),"no one"))
				{
					cout<<"Can not find this name in database.\n";
				}
			}
			break;
		default:
			cout<<"Incorrect choice";
		}
	}while(choice!=1&&choice!=2);
}

void add(fstream &addStudent)
{
	Student studentcmp;
	int id,age;
	char lastName[15],firstName[15];
	char score;
	cout<<"Please input the new student ID:\n(1~1000)?";
	cin>>id;
    //check if the ID is between 1~1000 
	do
	{
		if(id<1 || id>1000)
		{
			cout<<"Incorrect student ID";
			cout<<"\nPlease input the new student ID again:\n(1~1000)?";
			cin>>id;
		}
	}while(id<1 || id>1000);
    //move the "get" file pointer to the position and read the 
	//data into the ""studentcmp"
	addStudent.seekg((id-1)*sizeof(Student));
	addStudent.read(reinterpret_cast<char*>(&studentcmp),
		sizeof(Student));
	//if the position has no data(ID=0)
	if(studentcmp.getId()==0)
	{
		
		cout<<"Please input the first name:";
		cin>>firstName;
		cout<<"Please input the last name:";
		cin>>lastName;
		cout<<"Please input the age:";
		cin>>age;
		cout<<"Please input the score(A,B,C,D,E):";
		cin>>score;
        //set a Student object using the data
		Student student(id,lastName,firstName,age,score);

		cout<<"the new student you input is:\n"
		<<"Name:"<<student.getFirstName()<<student.getLastName()
		<<"\nID:"<<student.getId()
		<<"\nAge:"<<student.getAge()
		<<"\nScore:"<<student.getScore()
		<<"\nThe data has been added to the database"
		<<endl;
   //write the "student" into the potition 
	addStudent.seekp((id-1)*sizeof(Student));
	addStudent.write(reinterpret_cast<char*>(&student),
		sizeof(Student));
	}
	else
	{
		cout<<"This ID already exists!"
			<<" Fail to add. Please delete the ID first.\n";
	}
}
void deleteStudent(fstream &deleteStudent)
{
	Student student,student2,blankStudent;
	int choice;
	int id,idOfName;
	char firstName[10],lastName[10];

	cout<<"Please choose:"
		<<"\n1--search and delete by ID"
		<<"\n2--search and delete by name\n?";
	cin>>choice;
	switch (choice)
	{
	case 1:
		cout<<"Please input the ID:";
		cin>>id;
		//move the get file pointer to the position
		deleteStudent.seekg((id-1)*sizeof(Student));
		deleteStudent.read(reinterpret_cast<char*>(&student),
			sizeof(Student));
		//if the position has data (strcmp will return no 0)
		if(strcmp(student.getFirstName(),"no one"))
		{
			cout<<"the ID you want to delete is:\n"
				<<setiosflags(ios::left)
				<<setw(8)<<"ID"
				<<setw(15)<<"LastName"
				<<setw(15)<<"FirstName"
				<<setw(7)<<"Age"
				<<setw(5)<<"Score";
			student.showData();
			cout<<"\nIt has been deleted.\n";
        //move the put file pointer to the position
		deleteStudent.seekp((id-1)*sizeof(Student));
		//delete it
		deleteStudent.write(reinterpret_cast<char*>(&blankStudent),
			sizeof(Student));
		}
		else
			cout<<"This ID has no data.\n";
		break;
	case 2:
		cout<<"Please input the firstname:";
		cin>>firstName;
		cout<<"Please input the lastname:";
		cin>>lastName;
        // the "{" prevent "initialization of 'studentNum' is 
		//skipped by 'default' label"
		{   //studentNum is the numbers of student that have 
			//the same name
			for(int i=1,studentNum=0;i<=1000;i++)
			{
				deleteStudent.seekg((i-1)*sizeof(Student));
				deleteStudent.read(reinterpret_cast<char*>(&student),
					sizeof(Student));

				if(!strcmp(student.getFirstName(),firstName)&&
					!strcmp(student.getLastName(),lastName))
				{
					//the numbers of the student that match the
					//user's input.
					studentNum++;

					deleteStudent.seekg((i-1)*sizeof(Student));
					deleteStudent.read(reinterpret_cast<char*>(&student2),
						sizeof(Student));
					//if the ID(=i) has data,asigh it to "idOfName"
			        idOfName=i;

					if(studentNum==1)
						cout<<"Find "<<studentNum<<" student\n"; 
					else
						cout<<"Find "<<studentNum<<" students\n";
					
					cout<<"the ID you want to delete is:\n"
						<<setiosflags(ios::left)
						<<setw(8)<<"ID"
						<<setw(15)<<"LastName"
						<<setw(15)<<"FirstName"
						<<setw(7)<<"Age"
						<<setw(5)<<"Score"<<endl;
					student2.showData();
					cout<<"It has been deleted."
						<<endl;
					//delete it
					deleteStudent.seekp((idOfName-1)*sizeof(Student));
					deleteStudent.write(reinterpret_cast<char*>(&blankStudent),
						sizeof(Student));
				}
			}
		}
		if(!strcmp(student2.getFirstName(),"no one"))
		{
			cout<<"Can not find this name in database.\n";
		}
		break;
	default:
		cout<<"Incorrect choice\n";
	}
}

void cleanDatabase()
{
	char choice='N';
	cout<<"Really clean all the data?"
		<<"\npress Y to confirm or press any other key to cancel\n";
	cin>>choice;
	if(choice=='y'||choice=='Y')
	{
		cout<<"All the data has been cleaned.\n";
		//make a new blank file
		makeNewFile();
	}
}

void aboutMe()
{
	cout<<"\n"
        <<"This is my pensonal information:\n"
		<<"Name:Alex Sue\n"
		<<"Age:20\n"
		<<"Email:[e-mail]\n"
		<<"Interest:computer,game,music....\n"
		<<"School:South China University of Technology\n"
		<<"Class:2000 CS(4)\n"
		<<"Student ID:200035003203160\n";
}