Question

One more proposed pb from "struct" (taken from TutorialsPoint) - Given the code below complete the program with a function having this prototype:
void updateID( struct Books *book );
that eliminates the last 2 digits in the book_id of the book that is called for. Also, call the  function printBook(...) before and after calling the updateID(...) for the same book, so the change to the book id can be seen.

#include <iostream>
#include <cstring>

using namespace std;
void printBook( struct Books *book );

struct Books {
char title[50];
char author[50];
char subject[100];
int book_id;
};
int main() {
struct Books Book1; // Declare Book1 of type Book
struct Books Book2; // Declare Book2 of type Book

// Book 1 specification
strcpy( Book1.title, "Learn C++ Programming");
strcpy( Book1.author, "Chand Miyan");
strcpy( Book1.subject, "C++ Programming");
Book1.book_id = 6495407;

// Book 2 specification
strcpy( Book2.title, "Telecom Billing");
strcpy( Book2.author, "Yakit Singha");
strcpy( Book2.subject, "Telecom");
Book2.book_id = 6495700;

// Print Book1 info, passing address of structure
printBook( &Book1 );

// Print Book1 info, passing address of structure
printBook( &Book2 );

return 0;
}

// This function accept pointer to structure as parameter.
void printBook( struct Books *book ) {
cout << "Book title : " << book->title <<endl;
cout << "Book author : " << book->author <<endl;
cout << "Book subject : " << book->subject <<endl;
cout << "Book id : " << book->book_id <<endl;
}

Answer 1

Program in the bold reflects the change. If any further clarifications required please feel free to ask.

#include <iostream>
#include <cstring>

using namespace std;
void printBook( struct Books *book );
void updateID(struct Books *book);

struct Books {
char title[50];
char author[50];
char subject[100];
int book_id;
};
int main() {
struct Books Book1; // Declare Book1 of type Book
struct Books Book2; // Declare Book2 of type Book

// Book 1 specification
strcpy( Book1.title, "Learn C++ Programming");
strcpy( Book1.author, "Chand Miyan");
strcpy( Book1.subject, "C++ Programming");
Book1.book_id = 6495407;

// Book 2 specification
strcpy( Book2.title, "Telecom Billing");
strcpy( Book2.author, "Yakit Singha");
strcpy( Book2.subject, "Telecom");
Book2.book_id = 6495700;

// Print Book1 info, passing address of structure
printBook( &Book1 );

// Print Book1 info, passing address of structure
printBook( &Book2 );

//updating the id of book1
cout<<"book details before updation is performed"<<endl;
printBook( &Book1 );
updateID(&Book1 );
cout<<"book details After updation is performed"<<endl;
printBook( &Book1 );

// updating the id of book2
cout<<"book details before updation is performed"<<endl;
printBook( &Book2 );
updateID(&Book2);
cout<<"book details after updation is performed";
printBook( &Book2 );

return 0;
}

// This function accept pointer to structure as parameter.
void printBook( struct Books *book ) {
cout << "Book title : " << book->title <<endl;
cout << "Book author : " << book->author <<endl;
cout << "Book subject : " << book->subject <<endl;
cout << "Book id : " << book->book_id <<endl;
}

void updateID(struct Books *book)
{
/* example int a=12345;
int b;
float c;
b=a/100; =123 because b is integer variable,it will store integer value
c=a/100; =123.45 because c is float variable,it will store float value
*/
   book->book_id = book->book_id/100;
}