ass9.cpp

#include <iostream>
#include <fstream>
#include <cstring>
#include <iomanip>
#include<cstdlib>
#define max 50
using namespace std;
class Employee
{
    char name[max];
    int empid;
    int sal;
    char de[50];
    friend class FileOperations;
    public:	Employee()
    		{
   				strcpy(name,"");
   				empid=sal==0;
   				strcpy(de,"");
    		}
    		Employee(char name[max],int empid,int sal,char de[max])
    		{
    			strcpy(this->de,de);
    			strcpy(this->name,name);
    		
    			this->empid=empid;
    			this->sal=sal;
    		}
    		int getEmpId()
    		{
    			return empid;
    		}
    		void displayEmployeeData()
    		{
    			
    			cout<<endl<<empid<<"\t\t\t"<<name<<"\t\t\t"<<sal<<"\t\t\t"<<de;
    		}
};
class FileOperations
{
	fstream file;
	public:FileOperations(char *name)
		   {
			 //strcpy(this->name,name);
			 this->file.open(name,ios::in|ios::out|ios::ate|ios::binary);
		   }
		   void insertRecord(int empid,char name[max],int sal,char de[max])
		   {
			   Employee s=Employee(name,empid,sal,de);
			   file.seekp(0,ios::end);
			   file.write((char*)&s,sizeof(Employee));
			   file.clear();
		   }
		   void displayAllRecords()
		   {
			   Employee s;
			   file.seekg(0,ios::beg);
			   while(file.read((char *)&s,sizeof(Employee)))
			   {
				   s.displayEmployeeData();
			   }
			   file.clear();
		   }
		   void displayRecord(int empid)
		   {
			   Employee s;
			   file.seekg(0,ios::beg);
			   void *p;
			   while(file.read((char *)&s,sizeof(Employee)))
			   {
				   if(s.empid==empid)
				   {
					   s.displayEmployeeData();
					   break;
				   }
			   }
			   if(p==NULL)
				   throw "Element not present";
			   file.clear();
		   }
		   void deleteRecord(int empid)
		   {
			   ofstream newFile("new.txt",ios::binary);
			   file.seekg(0,ios::beg);
			   bool flag=false;
			   Employee s;
			   while(file.read((char *)&s,sizeof(s)))
			   {
				   if(s.empid==empid)
				   {
					   flag=true;
					   continue;
				   }
				   newFile.write((char *)&s,sizeof(s));
			   }
			   if(!flag)
			   {
				   cout<<"Element Not Present";
			   }
			   file.close();
			   newFile.close();
			   remove("Employee.txt");
			   rename("new.txt","Employee.txt");
			   file.open("Employee.txt",ios::in|ios::ate|ios::out|ios::binary);
		   }
		   ~FileOperations()
		   {
			   file.close();
			   cout<<"Closing file..";
		   }

};
int  main()
{
	ofstream newFile("Employee.txt",ios::app|ios::binary);
	newFile.close();
	FileOperations file((char *)"Employee.txt");
    int empid,sal,choice=0;
    char name[max],de[max];
    while(choice!=5)
    {
        cout<<"\n\n1) Add New Record\n";
        cout<<"2) Display All Records\n";
        cout<<"3) Display by RollNo\n";
        cout<<"4) Deleting a Record\n";
        cout<<"5) Exit\n";
        cout<<"Choose your choice : ";
        cin>>choice;
        switch(choice)
        {
            case 1 : //New Record
            		cout<<endl<<"Enter employee id and name : \n";
            		cin>>empid>>name;
            		cout<<"Enter sal  \n";
            		cin>>sal;
            		cout<<"Enter designation : \n";
            		cin>>de;
            		file.insertRecord(empid,name,sal,de);
            		break;
            case 2 :
            	
			   cout<<"Employee ID"<<"\t\t"<<"Name"<<"\t\t"<<"Salary"<<"\t\t"<<"designation\n";
            	cout<<"----------------------------------------------------------------------";	
					file.displayAllRecords();
            		break;
            case 3 :
            		cout<<"Enter employee id";
            		cin>>empid;
            		try
            		{
            			file.displayRecord(empid);
            		}
            		catch(const char *str)
            		{
            			cout<<str;
            		}
            		break;
            case 4:
            		cout<<"Enter employe id";
            		cin>>empid;
            		file.deleteRecord(empid);
            		break;
           case 5 :break;
        }

    }
}