Search function for books

Question

I was making a library program for trying to practice C++. I wanted to use a vector to store all the books, the books being a struct to hold the general things the books would have.

struct Book
{
 string bookName; // book's name
 string bookAuthor; // book's author
 string bookID; // a random generated string
 int bookType; // what type of book
};

The books in the library would be stored in a vector. To find one of these books I used a function that takes in a bookId parameter and uses it to find the book.

Book LibrarySystem::LocateBook(string bookId)
{
 /* May not be the fastest search algorithm */
 for (int i = 0; i <= mBooks.size(); i++)
 {
 Book result = mBooks[i];
 if (bookId == mBooks[i].bookID)
 {
 return result;
 } 
 else 
 { 
 cout << "FAILED TO FIND " + bookId << endl;
 }
 } 
}

This works but I was wondering if it could be faster. Looking at it, I am going through it one by one checking if the bookId is equal to the one provide in the parameter which seems slow.

I did do a small test to check if it all worked. I created a function:

string LibrarySystem::BookDataOutput(string bookId)
{
 Book book = LocateBook(bookId);
 string data = 
 "Book author: " + book.bookAuthor + "\n" +
 "Book name: " + book.bookName + "\n" +
 "Book type: " + to_string(book.bookType) + "\n" +
 "Book Id: " + book.bookID;
 return data;
}

Which outputs a single string with all the book's information. It uses LocateBook to find the the book with the bookId.

I run in main:

int main(int args, char* argv[])
{
 /* Seed the random generator */
 srand(time(NULL));
 LibrarySystem library;
 library.RegisterBook("Test1", "Test1", BOOK_TYPE::Adult, "test1");
 cout << library.BookDataOutput("test1") << endl;
 cin.get();
}

and the output is:

Book author: Test1
Book name: Test1
Book type: 5
Book Id: test1

Which matches all the information I provided.

Answer 1

Since your search is only by 1 parameter, a map<string,Book> would work a lot better than a vector.

map<string,Book> mBooks;
string LibrarySystem::BookDataOutput(string bookId)
{
 Book book = mBooks[bookId];
 string data = 
 "Book author: " + book.bookAuthor + "\n" +
 "Book name: " + book.bookName + "\n" +
 "Book type: " + to_string(book.bookType) + "\n" +
 "Book Id: " + book.bookID;
 return data;
}