Question

IN C++

My project will be a library management system. It will have seven functions.

It HAS to contain: classes, structures, pointers and inheritance.

fix code according to below

1. Add a new book

• allows the user to enter in book name and book code

  • Book code has to be in #

    • “Invalid book code”

  • “book name has been added to library”

• book code will be used to borrow books

2. Add a new user

• must use first

• user must add a user ID and username

  • User ID must be in #

    • “Invalid user ID”

  • “Welcome username”

• user ID is used for borrowing books

3. Borrow a book

• uses the book code to borrow a book

  • Book code must be in #

    • “Invalid book code”

  • “Username has borrowed book name”

• Borrowing a borrowed book

  • “This book is being borrowed by username”

• once a book is borrowed no one else can borrow it

• changes availability to unavailable in search a book

4. Return a book

• -returns the availability of the book to available

• enter in book code to return

  • Book code must be in #

    • “Invalid book code”

  • “Thank you for returning book name”

  • Changes availability of the book to available

5. Search a book

• enter in book code

  • “Invalid book code”

• shows availability

• the message “sorry this book is borrowed by username”

  • shows who borrowed the book and book name

6. Displays users and number of books they have

• Shows all user ID, Username and number of books they have

7. Exit

• Exits the program

What i have so far (modify this code):

most of it is written just fix up the mistakes

#include <iostream>

using namespace std;

//structure to store library data

struct library{

int code;

char title[20];

int status;

};

//structure to store user data

struct users{

int id;

char name[20];

int booksNumber;

};

int main()

{

int tempId,i,flag=0,j;

char tempName[20];

int tempCode;

struct users user_details[100];//variable to hold 100 userdetails

struct library book_details[100];//variable to hold 100 book details

int user_count=0,books_count=0;

int choice;

//this loop runs until 7 is entered

do{

cout <<"MENU \n";

cout << "1. Add a new book\n";

cout << "2. Add a new user\n";

cout << "3. Borrow a book\n";

cout << "4. Return a book\n";

cout << "5. Search a book\n";

cout << "6. Displays users and number of books they have\n";

cout << "7. Exit\n";

cout << "Enter your choice : ";

cin >> choice;

switch(choice){

//Adds a new book in to the database and increase book count by 1

case 1:

cout<<"Bookname : ";

cin >> book_details[books_count].title;

cout <<"Bookcode : ";

cin >> book_details[books_count].code;

book_details[books_count].status = 1;

books_count++;

break;

case 2:

//adds a new user details in to database

cout << "Enter UserId : ";

cin >> tempId;

//flag variable to check whether user exists or not

flag=1;

for(i=0;i<user_count;i++){

if(tempId==user_details[i].id){

cout << "UserId already taken";

flag=0;

break;

}

}

//if user is not taken creating user id and increase user_count by 1

if(flag){

user_details[user_count].id=tempId;

cout << "Enter Username : ";

cin >> user_details[user_count].name;

user_details[user_count].booksNumber=0;

user_count++;

}

break;

case 3:

cout << "Please enter your userId : ";

cin >> tempId;

flag = 0;

//check whether user exists or not using flag variable

for(i=0;i<user_count;i++){

if(user_details[i].id==tempId){

flag = 1;

break;

}

}

//if user exists then print his name and check fof the requested book

if(flag){

cout << "Welcome " << user_details[i].name << "\n";

//if user has taken less than 5 books

if(user_details[i].booksNumber<=5){

cout << "Please enter book code you want to borrow : ";

cin >> tempCode;

for(j=0;j<books_count;j++){

if(book_details[j].code==tempCode && book_details[j].status!=0){

book_details[j].status=0;

user_details[i].booksNumber++;

flag = 0;

break;

}

}

if(flag){

cout << "Book not found or it has been currently borrowed\n";

}

}

else{

cout << "The user reaches the max. allowed books to borrow\n";

}

}

else{

cout << "Username incorrect ;";

}

break;

case 4:

// to return the book issued to a user

cout << "Please enter book code :";

cin >> tempCode;

flag=0;

for(i=0;i<books_count;i++){

if(book_details[i].code==tempCode){

flag = 1;

break;

}

}

//once book is found then check for user id

if(flag){

if(book_details[i].status==0){

cout << "Enter user id ";

cin >> tempId;

flag = 0;

for(j=0;j<user_count;j++){

if(user_details[j].id==tempId){

flag =1;

break;

}

}

//if user and book details are found

if(flag){

user_details[j].booksNumber--;

book_details[i].status = 1;

}

else{

cout << "User not found\n";

}

}

else{

cout << "Book hasn't been borrowed\n";

}

}

else{

cout << "Invalid code\n";

}

break;

case 5:

//Searching a book using bookcode

cout << "Enter book code : ";

cin >> tempCode;

for(i=0;i<books_count;i++){

if(book_details[i].code==tempCode){

cout << book_details[i].code <<"\t"<< book_details[i].title <<"\t"<< book_details[i].status << "\n";

break;

}

}

break;

case 6:

//printing details of user using user_details structure

cout << "UserID UserName BorrowerNo\n";

for(i=0;i<user_count;i++){

cout << user_details[i].id <<"\t"<< user_details[i].name <<"\t"<< user_details[i].booksNumber<<"\n";

}

cout << "\n";

break;

case 7:

cout << "ThankYou";

break;

//if user input doesnot match with any of the case then ask him to enter data again

default:

cout << "Please enter valid input : ";

}

}while(choice!=7);

return 0;

}

Answer 1

#include <iostream>
#include <sstream>
#include <cstring>
#include<string>

using namespace std;

//structure to store library data

struct library{

int code;

char title[30];

int status;

};

//structure to store user data

struct users{

int id;

char name[20];

int booksNumber;

};

bool isNumber(string s)
{
for (int i = 0; i < s.length(); i++)
if (isdigit(s[i]) == false)
return false;
  
return true;
}

int main()

{

int tempId,i,flag=0,j;

char tempName[20];

int tempCode;

struct users user_details[100];//variable to hold 100 userdetails

struct library book_details[100];//variable to hold 100 book details

int user_count=0,books_count=0;

int choice;

//this loop runs until 7 is entered

do{

cout <<"MENU \n";

cout << "1. Add a new book\n";

cout << "2. Add a new user\n";

cout << "3. Borrow a book\n";

cout << "4. Return a book\n";

cout << "5. Search a book\n";

cout << "6. Displays users and number of books they have\n";

cout << "7. Exit\n";

cout << "Enter your choice : ";
string str="";
      
cin >> str;

  
// Function returns 1 if all elements
// are in range '0-9'
if (isNumber(str)) {
   stringstream geek(str);
geek >> choice;

switch(choice){

//Adds a new book in to the database and increase book count by 1

case 1:
   {
  

cout<<"Bookname : ";
cin>>book_details[books_count].title;
cout <<"Bookcode : ";
       string str="";
      
cin >> str;

  
// Function returns 1 if all elements
// are in range '0-9'
if (isNumber(str)) {
  

// object from the class stringstream
       stringstream geek(str);
  
// The object has the value 12345 and stream
// it to the integer book_details[books_count].code
  
       geek>>book_details[books_count].code;
book_details[books_count].status = 1;

books_count++;
cout<<"Book name has been added to library\n";
  
  
break;
  
   }else
   {
  
cout << "Invalid Book Code";
break;
}
//book_details[books_count].code

}
case 2:
{

//adds a new user details in to database

cout << "Enter UserId : ";

string str="";
      
cin >> str;

  
// Function returns 1 if all elements
// are in range '0-9'
if (isNumber(str)) {
  

// object from the class stringstream
       stringstream geek(str);
  
// The object has the value 12345 and stream
// it to the integer tempId
  
       geek>>tempId;

//flag variable to check whether user exists or not

flag=1;

for(i=0;i<user_count;i++){

if(tempId==user_details[i].id){

cout << "UserId already taken\n";

flag=0;

break;

}

}

//if user is not taken creating user id and increase user_count by 1

if(flag){

user_details[user_count].id=tempId;

cout << "Enter Username : ";

cin >> user_details[user_count].name;

user_details[user_count].booksNumber=0;

user_count++;

}
  
  
break;
  
   }else
   {
  
cout << "Invalid UserId\n";
break;
}

}
case 3:
{

cout << "Please enter your userId : ";
       string str="";
      
cin >> str;

  
// Function returns 1 if all elements
// are in range '0-9'
if (isNumber(str)) {
  

// object from the class stringstream
       stringstream geek(str);
  
// The object has the value 12345 and stream
// it to the integer tempId
  
       geek>>tempId;

flag = 0;

//check whether user exists or not using flag variable

for(i=0;i<user_count;i++){

if(user_details[i].id==tempId){

flag = 1;

break;

}

}

//if user exists then print his name and check fof the requested book

if(flag){

cout << "Welcome " << user_details[i].name << "\n";

//if user has taken less than 5 books

if(user_details[i].booksNumber<=5){

cout << "Please enter book code you want to borrow : ";
string tempcodde;
cin >> tempcodde;
if (isNumber(tempcodde)) {
  

// object from the class stringstream
       stringstream geek(tempcodde);
  
// The object has the value 12345 and stream
// it to the integer tempId
  
       geek>>tempCode;
}
else{
cout<<"Invalid book code \n";
break;
}

for(j=0;j<books_count;j++){

if(book_details[j].code==tempCode && book_details[j].status!=0){

book_details[j].status=0;

user_details[i].booksNumber++;

flag = 0;

break;

}

}

if(flag){

cout << "Book not found or it has been currently borrowed\n";

}

}

else{

cout << "The user reaches the max. allowed books to borrow\n";

}

}

else{

cout << "Username incorrect ;";

}

break;
   }else
   {
  
cout << "Invalid UserId\n";
break;
}

}
case 4:

// to return the book issued to a user

cout << "Please enter book code :";

cin >> tempCode;

flag=0;

for(i=0;i<books_count;i++){

if(book_details[i].code==tempCode){

flag = 1;

break;

}

}

//once book is found then check for user id

if(flag){

if(book_details[i].status==0){

cout << "Enter user id ";

cin >> tempId;

flag = 0;

for(j=0;j<user_count;j++){

if(user_details[j].id==tempId){

flag =1;

break;

}

}

//if user and book details are found

if(flag){

user_details[j].booksNumber--;

book_details[i].status = 1;

}

else{

cout << "User not found\n";

}

}

else{

cout << "Book hasn't been borrowed\n";

}

}

else{

cout << "Invalid code\n";

}

break;

case 5:

//Searching a book using bookcode

cout << "Enter book code : ";

cin >> tempCode;

for(i=0;i<books_count;i++){

if(book_details[i].code==tempCode){

cout << book_details[i].code <<"\t"<< book_details[i].title <<"\t"<< book_details[i].status << "\n";

break;

}

}

break;

case 6:

//printing details of user using user_details structure

cout << "UserID UserName BorrowerNo\n";

for(i=0;i<user_count;i++){

cout << user_details[i].id <<"\t"<< user_details[i].name <<"\t"<< user_details[i].booksNumber<<"\n";

}

cout << "\n";

break;

case 7:

cout << "ThankYou";

break;

//if user input doesnot match with any of the case then ask him to enter data again

default:

cout << "Please enter valid input range from 1-7: \n";

}
}
else
{
   cout<<"you should check your input . it may be string or specific symbol\n";
}
}while(choice!=7);

cout<<"Please enter valid value ";

}

now i made some changes like entering char in the choice but the book name problem is still same... i m trying to finding new ways to solve the problem ,, the problem occurs because of multiple spaces..

input - the ways of kings contain 4 whitespace so the IDE treats it as new line or new input for the code.. thats why the problem occurs instead of using white space you should try "the_ways_of_kings" . well i am trying to finding new ways ..till then you can use this code.. i will provide the solution as soon as possible..