DATA-FILE-HANDLING-QUESTION-BANK-XII-CS




Q1. Write a function in C++ to count and display the number of line starting with alphabet ‘A’ present in a text file “LINES.TXT”.                                                    
Example: if the file LINES.TXT contains the following lines:
A boy is playing there.
There is a playground.
An airplane is in the sky.
Alphabets and numbers are allowed in the password.
Then the function should display the output as 3.
………………ANSWER…………………………..
#include<fstream.h>
#include<conio.h>
void main()
 {
  ifstream file("LINES.txt",ios::in);
  if(!file) { cout<<" ERROR in OPENING FILE. "; return;}
  char oneline[80]; int nol=0;
   while(file)
     { file.getline(oneline,80);
       if(oneline[0]=='A')  nol++;
     }
     cout<<"\n NUMBER OF LINES IN THE SPECIFIED TEXT FILE = "<<nol;
  file.close();
  getch();
 }
…………………………………………………….


Q2.Write a function in C++ to count the number of lines and words present in a text file “san.txt”. 
………………………ANSWER………………………………
#include<fstream.h>
#include<conio.h>
void main()
 {
  ifstream file("san.txt",ios::in);
  if(!file) { cout<<" ERROR in OPENING FILE. "; return;}
  char oneline[80]; int nol=0;
   while(file)
     { file.getline(oneline,80);
       nol++;
     }
     nol--;
     cout<<"\n TOAL NUMBER OF LINES IN THE SPECIFIED TEXT FILE = "<<nol;
  file.close();
  file.open("san.txt",ios::in);
  if(!file) { cout<<" ERROR in OPENING FILE. "; return;}
  char oneword[80]; int now=0;
   while(file)
     { file>>oneword;
       now++;
     }
     now--;
     cout<<"\n TOAL NUMBER OF WORDS IN THE SPECIFIED TEXT FILE = "<<now;
  file.close();
  getch();
 }
……………………………………………………………………                                                                                                              

Q3.Write function to count the number of digits present in the given text file.
……………………………………………………………………
#include<fstream.h>
#include<conio.h>
void main()
 {
  ifstream file("SAMPLE.txt",ios::in);
  if(!file) { cout<<" ERROR in OPENING FILE. "; return;}
  char c; int nod=0;
   while(file)
     { file.get(c);
       if(c>'0' && c< '9') nod++;
     }
  cout<<"\n TOAL NUMBER OF DIGITS IN THE SPECIFIED TEXT FILE = "<<nod;
  file.close();
  getch();
 }
…………………………………………………………………………

Q4.Write C++ function display_male() that displays the details of all the Male members of the binary file “society.dat” containing the details from the following class:                                                                                                                                 
class Society {
              int memid;
              char memname[20];
              char gender; // ‘M’ or ‘F’
           public:
              void setdata();
              void display();
              char getgender(){ return gender;}
     };
………………………………………………………………………………………………………………………………
A   COMPLETE   PROGRAM  TO CREATE  A  NEW   FILE   AND  DISPLAY   CONTENT  OF  IT
……………………………………................................................................................................
#include<fstream.h>                            
#include<conio.h>
#include<stdio.h>
class society {
              int memid;
              char memname[20];
              char gender;    // 'M' or 'F'
           public:
              void setdata();
              void display();
              char getgender(){ return gender;}
               };

void society::setdata()
{
    cout<<"\n Please enter member id : "; cin>>memid; ;
    cout<<"\n Please enter member name :"; gets(memname);
    cout<<"\n Please enter gender  : M/F "; cin>>gender;
}
void society::display()
{
    cout<<"\n Member id : "; cout<<memid;
    cout<<"\n Member name :"; cout<<memname;
    cout<<"\n  Gender  : M/F "; cout<<gender;//vvv
}

void main()
 {
   society soc;
  fstream file("data",ios::out|ios::binary);  //create a new file "data"
  if(!file) { cout<<" ERROR in OPENING FILE. "; return;}
  int i=1, n;
  cout<<"\n How many records  you want to enter in specified Binary file :";
  cin>>n;
   while(i<=n)
     { soc.setdata();
       file.write((char *)&soc,sizeof(soc));
       i++;
     }
     file.close();

     file.open("data",ios::in|ios::binary); //open file in read only mode
     cout<<"\n CONTENT OF BINARY FILE (INCLUDING BOTH MALE AND FEMALE ) : \n ";
        i=1;
        while(i<=n)
                {
                 file.read((char *)&soc,sizeof(soc));
                 soc.display();
                 i++;
               }

      cout<<"\n details of only Male members are  : \n ";
      file.seekg(0,ios::beg);
      while(file.read((char *)&soc,sizeof(soc)))
          {
                if (soc.getgender()=='M' ||soc.getgender()=='m')
                     soc.display();
           }
    
  file.close();
  getch();
 }
…………………………………………………………………………………………………………………………..
function display_male() that displays the details of all the Male members of the binary file “society.dat” containing the details from the following class

………………………………………… ANSWER………………………..
Void display_male()  {   
          ifstream f("data",ios::in|ios::binary); //open file in read only mode;
         cout<<"\n details of only Male members are  : \n ";
          while(f.read((char *)&soc,sizeof(soc)))
               {
                   if (soc.getgender()=='M' ||soc.getgender()=='m')
                          soc.display();
                }    
  file.close(); }
Q5.Assuming the class ZOO given below, write functions in C++ to do following:                                                                                            
i.                    Write the objects of ZOO to a binary file.
ii.                  Read the objects of ZOO from binary file and display them on screen.
            class ZOO      {                       char location[20];
                                                          int no_of_animals[10];
                                               public:
                                                     void readdata()
                                                           {cin>>location; gets(no_of_animals);                }                                    
                                                     void writedata()
                                                            { cout<<location<<” ”<<no_of_animals<<endl;}
                                  };
…………………………………………………………….
void Write2File(ZOO   z)
{
  ofstream file("data",ios::out|ios::binary);  //create a new file "data"
  if(!file) { cout<<" ERROR in OPENING FILE. "; return;}
  int i=1, n;
  cout<<"\n How many records  you want to enter in specified Binary file :";
  cin>>n;
   while(i<=n)
     { z.readdata();
       file.write((char *)&z,sizeof(z));
       i++;
     }
     file.close();
}

void ReadFromFile()
{
  ifstream file("data",ios::in|ios::binary);  //read from  file "data"
  if(!file) { cout<<" ERROR in OPENING FILE. "; return;} 
   while(file.read((char *)&z,sizeof(z)))
     { z.writedata();  }
     file.close();
}
Q6.Following is the structure of each record in a data file named “Colony.dat”    
struct Colony {
            char colony_code[10];
            char colony_name[10];
            int no_of_people;  };
Wite a function to update the file with a new value of No_of_people. The value of colony_code and no_of_people  are read during the execution of the program.

……………………………………………  ANSWER ……………………………………………………
void UpdateFile()
{
  Colony col;
  ifstream file("colony",ios::in|ios::binary);  //read from  file "data"
  if(!file) { cout<<" ERROR in OPENING FILE. "; return;} 
  cout<<”\n  Enter value of colony code  : “;
 c in>>col_code;
 c out<<”\n  Enter no_of_people  : “;
 cin>> No_of_people  ;

   while(file.read((char *)&col , sizeof(col)))
     {  
               if(col.colony_code==col_code)
                            col.no_of_people =  No_of_people  ;
    }
     file.close();
}
Q7.Assuming the class Computer as follows:                                                                     
Class computer  {
char chiptype[10];
int speed;
public:
void getdetails( )
{
gets(chiptype);
cin>>speed;
}
void showdetails( )
{
cout<<”Chip”<<chiptype<<”Speed=”<<speed<<endl;
}
};
Write a function readfile() to read all the records present in an already existing binary file “SHIP. DAT” and display them on the screen, also count the number of records present in the file.
……………………………………………….ANSWER…………………………………………
void readfile()
{
class computer comp  ;
int count=0;
ifstream file("SHIP.DAT",ios::in|ios::binary);  //read from  file "data"
  if(!file) { cout<<" ERROR in OPENING FILE. "; return;}
cout<<”\n CONTENT OF GIVEN BINARY FILE :\n”;
   while(file.read((char *)&comp , sizeof(comp)))
                                            {
                                                   comp.showdetails();
                                                  count++;
                                           }
cout<<”\n Total no of records = “<<count;
     file.close();
}                     



Q8. Observe the following program segment and fill in the blanks marked as statement 1 and statement 2                                                            
#include<fstream.h>
class Student{
    int id; char name[20], char hobby[20];
   public:
    void entry();
    void modify();
    int getid(){ return id;}
 };
void changehobby(int num)
{
    Student me;
     fstream file;
     f.open(“info.dat”,ios::in|ios::out|ios::binary);
     while(file.read((char *) &me, sizeof(me)))
        {
            if(num==me.getid())
           {
                 me.modify();             
                 long fp =……………………….. // Statement 1 to acquire the
                                                  //  position of the read pointer.
              ……………………………………….. // Statement 2 to place the write
                                                    //pointer to the proper position
                                                   //for writing.
        file.write((char *) &me, sizeof(me))
           }
         }
      file.close();
  }

……………………………………………….ANSWER…………………………………………
         fp = file.tellg();        //statement 1
                            file.seekp(fp-sizeof(me), ios :: beg); // statement 2

Q9. Observe the program segment given below carefully and fill the blanks marked statement 1 and statement 2 using seekg( ) and tellg( ) function for performing the required task.                                                                                                                  
#include<fstream.h>
class Employee
{int Eno;
char Ename[30];
public:
int Countrec( );        //Function to count the total number of records
};
int Employee:: Countrec( )
{
fstream File;
File.open(“Emp.Dat”,ios::binary||ios::in);
___________                                 // Statement 1
int Bytes = ________________ // Statement 2
int count = Bytes/sizeof(Employee);
File.close( );
return count;
}
……………………………………………….ANSWER…………………………………………
                                   File.seekg(0,ios::end);        //statement 1
                                                      File.tellg();                            // statement 2
Q10. Observe the program segment given below carefully, and answer the question that follows:

                  class Examiner
                  {
                        int eno;                                  / / examiner’s number
                       char ename[20];                 / / examiner’s name
                       char eadd[25];                     / / examiner’s address
                       int exp;                                   / / examiner’s experience
                   public:
                         void read_data();
                         void out_data();
                         void revised();        // function to make revisions in the experience
                        int chno();                // returns the new experience        
        };

void experience (int revno)
{fstream fin;
fin.open(“exam.dat”ios::binary|ios::in|ios::out);
Examiner ex;
int rec=0;got=0;
while(!got && fin.read((char*)&ex,sizeof(ex)))
{  if (revno=ex.chno())
                        {cout<<”enter the new experience”;
ex.revised();            
___________________                         / / statement 1       
___________________                         / / statement 2
got=1;
}
rec++; }
fin.close(); }
 Write the statement 1 to position the file pointer at the beginning of the record for which the examiner’s  number matches with the argument passed, and the statement 2 to write      the updated record at that position.
……………………………………………….ANSWER…………………………………………
          fin.seekp(fin.tellg( ) – sizeof(i));        //statement 1
                             fin.write((char*) &ex ,  sizeof (ex)); // statement 2
Q11. Observe the program segment and answer the question that follows: 
 class item  
   {
     int item_no;   char item_name[20];
 public:
    void enterDetails( ); void showDetail( );
    int getItem_no( ){ return item_no;}
  };
void modify(item x )   {         fstream File;
      File.open( “item.dat”,…………………..     ) ; //parameter missing item i;
       while(File .read((char*) & i , sizeof (i)))
           {   if(x . getItem_no( ) = = i . getItem_no( ))
                             {
                                   File.seekp(File.tellg( ) – sizeof(i));
                                                      File.write((char*) &x ,  sizeof (x));
                               }
                  else
                        File.write((char*) &i ,  sizeof (i));
           }
       File.close() ;   }
If the function modify( ) modifies a record in the file “ item.dat “ with the values of item x passed as argument, write the appropriate parameter for the missing parameter in the above code, so as to  modify record at its proper place.
…………………………. ANSWER………………
File.open( “item.dat”,ios::ate|ios::binary)

Q12. A file named as “STUDENT.DAT” contains the student records, i.e. objects of class student. Write the command to open the file to update a student record.(Use suitable stream class and file mode(s).
………………………………… ANSWER……………………………………..
fstream   f(“STUDENT.DAT”,ios::ate|ios::binary)        
                                                
Q13.Observe the program segment carefully and answer the question that follows: (2M)
class member      { 
int member_no;
char member_name[20];
public: 
void enterDetails( ); void showDetail( );
int getMember_no( ){ return member_no;}
};
void update(member NEW ){
    fstream File;
     File.open( “member.dat”, ios::binary|ios::in|ios::out) ; member i;
     while(File .read((char*) & i , sizeof (i)))
        {
           if(NEW . getMember_no( ) = = i . getMember_no( ))
               {   File.seekp(………………., ios::cur ) //Paremeter Missing
                  File.write((char*) &NEW , sizeof (NEW));
              } 
        }        File.close() ;}

If the function update( ) is supposed to modify a record in the file “ member.dat” with the values of member NEW passed as argument, write the appropriate parameter for the missing parameter in the above code, so as to  modify record at its proper place.
-------------------------------ANSWER  ------------------------
 File.seekp(  -sizeof(i) , ios::cur)

Q14. A file named as “STUDENT.DAT” contains the student records, i.e. objects of class student. Assuming that the file is just opened through the object FILE of fstream class, in the required file mode, write the command to position the put pointer to point to second record from the last record.   
…………………………. ANSWER……………………..
FILE.seekp(-2*sizeof(student) , ios::end);   
                                 

Q15. A file named as “STUDENT.DAT” contains the student records, i.e. objects of class student. Assuming that the file is just opened through the object FILE of fstream class, in the required file mode, write the command to position the get pointer to point to fifth record from the beginning.   
…………………………. ANSWER……………………..
FILE.seekg(4*sizeof(student) , ios::beg);       
Q16. Read the code given below and answer the question: 
void main( )
{  char ch = ‘A’;
fstream outFile (“data.dat”, ios::out); outFile<<ch<<ch;  }
If the file contains GOOD before execution, what will be the contents of the file after execution of this code?
…………………………. ANSWER……………………..
Content of file after execution of the above code will be:
“AA”

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