I was wondering if there is a way to get a date without writing your own function. Something such as accessing the date set for the system. I tried
char dateStr[9];
_strdate(dateStr);
with the included time header, but I got compiler error ISO C++ forbids declaration of _strdate with no type. I thought _strdate was already declared and defined in the header so it wouldn’t need a type definition. Could the problem be that I have those 2 lines inside of a struct? Are there any better way to store a date? Thanks.
#include "std_lib_facilities.h"
//Classes-----------------------------------------------------------------------
class Book{
public:
Book(){}; // default constructor
//operators
friend ostream& operator<<(ostream& out, const Book& val);
bool Book::operator==(const Book& check);
//member functions
string title();
string author();
string genre();
int copyright();
void ISBN();
bool checkout();
private:
string title_;
string author_;
string genre_;
int copyright_;
int ISBN1;
int ISBN2;
int ISBN3;
char ISBN4;
bool checkout_;
};
class Patron{
public:
Patron(){}; //default constructor
//member functions
string name();
int libnumber();
double setfee();
private:
string name_;
int libnumber_;
double libfees;
};
class Library{
public:
vector<Book> books;
vector<Patron> patrons;
struct Transaction{
Book book;
Patron patron;};
vector<Transaction> transactions;
};
// Error Function---------------------------------------------------------------
void _error(const string& s)
{
cout << endl;
cout << "Error: " << s << endl;
cout << endl;
}
// Book Member Functions--------------------------------------------------------
string Book::title()
{
cout << "Title: ";
getline(cin,title_);
cout << endl;
return title_;
}
string Book::author()
{
cout << "Author: ";
getline(cin,author_);
cout << endl;
return author_;
}
string Book::genre()
{
cout << "Genre(Fiction, Nonfiction, Periodical, Biography, Children): ";
cin >> genre_;
cout << endl;
if((genre_!="Fiction")&&(genre_!="Nonfiction")&&(genre_!="Periodical")&&
(genre_!="Biography")&&(genre_!="Children")) _error("Invalid genre.");
else return genre_;
}
int Book::copyright()
{
cout << "Copyright: ";
cin >> copyright_;
cout << endl;
return copyright_;
}
void Book::ISBN()
{
cout << "ISBN (4 entries. Use spaces): ";
cin >> ISBN1 >> ISBN2 >> ISBN3 >> ISBN4;
if((ISBN1<0) || (ISBN2<0) || (ISBN3<0) || (ISBN1>9) || (ISBN2>9) || (ISBN3)>9)
_error("Must be single digit.");
else if(!isdigit(ISBN4) && !isalpha(ISBN4))
_error("Must be single digit or letter.");
else{ cout << endl;
return;}
}
bool Book::checkout()
{
char check;
cout << "Checked out?(Y or N): ";
cin >> check;
switch(check){
case 'Y':
cout << endl;
return true;
break;
case 'N':
cout << endl;
return false;
break;
default:
_error("Must be Y or N.");}
}
// Patron Member Functions------------------------------------------------------
string Patron::name()
{
cout << "Name: ";
getline(cin,name_);
cout << endl;
return name_;
}
int Patron::libnumber()
{
cout << "Libnumber: ";
cin >> libnumber_;
cout << endl;
return libnumber_;
}
double Patron::setfee()
{
cout << "Fee due: ";
cin >> libfees;
cout << endl;
return libfees;
}
// Patron Helper Functions------------------------------------------------------
bool isfee()
{
char isfee_;
cout << "Does patron have fee due?(Y or N): ";
cin >> isfee_;
cout << endl;
if((isfee_!='Y') && (isfee_!='N')) _error("Must use Y or N.");
else return(isfee_=='Y');
}
// Operator Overloads-----------------------------------------------------------
ostream& operator<<(ostream& out, const Book& val){
out << "Title: " << val.title_ << endl;
out << "Author: " << val.author_ << endl;
out << "ISBN: " << val.ISBN1 << "-" << val.ISBN2 << "-" << val.ISBN3 << "-" << val.ISBN4 << endl;
out << endl;
return out;}
bool Book::operator==(const Book& check){
return((ISBN1 == check.ISBN1) && (ISBN2 == check.ISBN2) && (ISBN3 == check.ISBN3)
&& (ISBN4 == check.ISBN4));}
// Main Helpers-----------------------------------------------------------------
void runBook()
{
Library bookstore;
char notfinished;
bool bookfinished = false;
while(!bookfinished)
{
Book book;
book.title();
book.author();
book.genre();
book.copyright();
book.ISBN();
book.checkout();
bookstore.books.push_back(book);
cout << "Do you wish to store another book?(Y or N): ";
cin >> notfinished;
if(notfinished == 'Y'){
cin.ignore();
cout << endl;}
else if(notfinished == 'N'){
bookfinished = true;
cout << endl;}
else _error("Must be Y or N");
}
}
void runPatron()
{
Library patronstore;
bool patronfinished = false;
char notfinished;
while(!patronfinished)
{
Patron patron;
patron.name();
patron.libnumber();
if(isfee()){
patron.setfee();}
cin.ignore();
runBook(); // Call book function
patronstore.patrons.push_back(patron);
cout << "Is there another patron?(Y or N): ";
cin >> notfinished;
if(notfinished == 'Y'){
cin.ignore();
cout << endl;}
else if(notfinished == 'N') patronfinished = true;
else _error("Must be Y or N");
}
}
// Main-------------------------------------------------------------------------
int main()
{
runPatron();
keep_window_open();
}
If you go to class Library and into the Transaction struct, that is where I want to store the date.
Where to start? Difficult to tell without seeing the code, but here’s some thoughts.
First, you should probably NOT store the date as a character array within your struct because that will make manipulation of it awkward. Better to store it in it’s native form as a time_t, and convert it to/from strings as required.
Second, if you must store it as ascii, don’t store it as char[]. You’re just asking for buffer overruns etc. Use string or vector
However, I think the real answer to your question concerns constructors. If you want Transaction to hold a date, then define it like this
If you want transactions to be datestamped, then assign the date in the constructor
Now, whenever you create a Transaction, it will automatically be filled with the return value from _strdate, whatever that is. Here’s how I’d do it with time_t.