INSERTION

-

Insertion

In this blog I have explained the insertion() function in detail. Aim of our project is to create the database of the books in the library. We have to maintain all the records and details of all the books. 
So the important thing is to insert the data into the file in well structured format. 
To do this we have check first that the file is opened successfully or not.For that we put condition in if loop 'file.is_open()'. This will return true if file is opened successfully otherwise it will return false.
Once it enters in if loop it will take all the inputs from the user like name of the book, name of the author, publication, number of pages etc.


void insertion()
    {
 fstream file;
        file.open("cp.txt",ios::out|ios::app);
        books b1;
Function starts with creating the object of fstream class. As we have to write in the file we have to open it and also we have to append the data in it. So the next line we used the file.open() function. The parameters ios::out |ios::app  make file to open in write mode and append mode.  Book b1 is structure.


  if(file.is_open())
          {
            cout<<endl<<"File opened succesfully ";
            cout<<endl<<"\nEnter the name of the book ";
            cin>>b1.name;
            cout<<"Enter the name of the author ";
            cin>>b1.author;
            cout<<"Enter the name of the publication ";
            cin>>b1.publication;
            cout<<"Enter the number of pages ";
            cin>>b1.pages;
            cout<<"Enter the count of the books ";
            cin>>b1.counti;
            //cout<<b1.counti;
            file<<"\n\n"<<"BOOK "<<number++;
            file<<"\n";

 These are the simple lines of code that are just taking the input from the user.
 After taking all inputs successfully  next step is to insert data in structured format.

             file.fill(' ');
            file.setf(ios::left,ios::adjustfield);
            file.width(20);
            file<<"name"<<b1.name<<endl;

             file.fill(' ');
            file.setf(ios::left,ios::adjustfield);
            file.width(20);
            file<<"author"<<b1.author<<endl;

             file.fill(' ');
            file.setf(ios::left,ios::adjustfield);
            file.width(20);
            file<<"publication"<<b1.publication<<endl;

             file.fill(' ');
            file.setf(ios::left,ios::adjustfield);
            file.width(20);
            file<<"pages"<<b1.pages<<endl;

             file.fill(' ');
            file.setf(ios::left,ios::adjustfield);
            file.width(20);
            //cout<<b1.counti;
            //fflush(stdin);
            file<<"count"<<b1.counti<<endl;

           file.close();
          copying();
          writing();
          }
       else
         cout<<endl<<"Error in opening the file";

     }


file.setf(ios::left,ios::adjustfield)  is used to write a data in the file in specific format. It forces text in fixed width field to be output with left justification.

The field width determines the minimum number of characters to be written in some output representations. If the standard width of the representation is shorter than the field width, the representation is padded with fill characters at a point determined by the format flag adjustfield (one of left, right or internal).

After inserting all the data file is closed using function file.close().
In case if file is not opened it will go into the else loop and print the message "Error in opening the file"
                                                       Before inserting the data

                                        
                                                      After inserting the data

Comments

Post a Comment

Popular posts from this blog

SEARCHING

-
Image
SEARCHING FUNCTION is used to find the query according to the NAME OF THE BOOK and NAME OF THE AUTHOR. First all the information is copied from CP.txt to the array YASH [] by using COPYING () function. For searching linear search is used. Linear search is a method for finding an element within a list. It sequentially checks each element of the list until a match is found or the whole list has been searched. In this case the loop will iterate until i<=top which is also can be considered as EOF (End Of File) Each name and author are checked ,once a proper argument is found then the information Name of the book, Name of Author, Publication, No of pages and no. of copies are displayed.
Read more

ORDER BY PART-2

-
Image
This part of the blog is in continuation with ORDER BY PART-1 where we discussed the algorithm of quick sort. Now here we will see the code where it is applied to the program. Here if file is not in array then we call it to array first. Then we have two choices whether to sort by pages or by count. This choice will be passed as an argument to sorting(), where we will have a switch case. Arguments low and top are the end points of array for quick sort. If it is a valid array i.e. low<high then go to function parti() which returns the updated pivot element. sorting(low,pi-1,choice); is for left side of pivot. sorting(pi+1,high,choice); is for right part of pivot. Here according to choice we perform the algorithm on either pages or count attribute. Inside switch we select pivot element which is always the last element of array. In the above part of code, again according to the choice the algorithm proceeds. Swapping of array elements take place as per th...
Read more

GROUP BY

-
Image
In this blog we would like to perform the group by operation of sql in cpp.The group by operation helps in grouping the rows of a particular attribute having same values.This is one of the most important feature of sql.Let's code it down. Initially we will copy the data from the secondary memory to the primary memory using the copying function as discussed above. We are basically going to perform grouping by single attribute and the user would be given a choice to select the attribute by which he wants to perform the grouping operation.So here we provide the user with a small menu for selecting the attributes. The user enters his choice and it is stored in the choice variable.                      int choice;            cout<<endl<<"\nEnter the attribute by which you want to group the books ";            cout<<endl<<"\n1.Name\n2.Author\n3.Pu...
Read more