Simple database: Difference between revisions
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[28.3.2018 15:06:18][cd][Horor][Movie name]
[28.3.2018 15:06:18][dvd][Horor][Movie name][Fiction][Movie name]
</pre>
=={{header|C++}}==
<syntaxhighlight lang="c++">
#include <algorithm>
#include <cstdint>
#include <fstream>
#include <iostream>
#include <string>
#include <vector>
const std::string filename = "Contacts.dat";
class Contact {
public:
Contact(const std::string& aName, const std::string& aBirth_Date, const std::string& aState,
const std::string& aRelation, const std::string& aEmail)
: name(aName), birth_date(aBirth_Date), state(aState), relation(aRelation), email(aEmail) { }
std::string get_relation() const {
return relation;
}
std::string to_string() const {
return name + ", " + birth_date + ", " + state + ", " + relation + ", " + email;
}
bool operator<(const Contact& other) const {
return birth_date > other.birth_date;
}
private:
std::string name, birth_date, state, relation, email;
};
std::vector<Contact> contacts = { };
Contact parse(std::string entry) {
std::vector<std::string> parts;
uint64_t position = 0;
while ( ( position = entry.find(", ") ) != std::string::npos ) {
parts.emplace_back(entry.substr(0, position));
entry.erase(0, position + 2);
}
return Contact(parts[0], parts[1], parts[2], parts[3], entry);
}
void write_file(const std::string& new_entry) {
std::fstream database(filename, std::ios::out | std::ios::app);
if ( database.is_open() ) {
database << new_entry;
database.close();
} else {
std::cerr << "Unable to open database '" << filename << "' for writing" << std::endl;
}
}
// Open the file if it exists, otherwise create a new empty file.
void read_file() {
std::fstream database(filename, std::ios::in | std::ios::app);
if ( database.is_open() ) {
std::string entry;
while ( std::getline(database, entry) ) {
contacts.emplace_back(parse(entry));
}
database.close();
} else {
std::cerr << "Unable to open database '" << filename << "' for reading" << std::endl;
}
}
void add_new_entry() {
std::cout << "Type the new entry, without inverted commas, in the format:" << std::endl;
std::cout << "Name, Birth_Date, State, Relation, Email" << std::endl;
std::string new_entry;
std::getline(std::cin, new_entry); // Consumes an end-of-line character in the input stream
std::getline(std::cin, new_entry);
Contact contact(parse(new_entry));
contacts.emplace_back(contact);
write_file(new_entry);
std::cout << "The contact \"" << new_entry << "\" has been added to the database" << std::endl;
}
void show_latest_entry() {
if ( ! contacts.empty() ) {
std::cout << "The latest entry is: " + contacts.back().to_string() << std::endl;
} else {
std::cout << "There are currently no entries in the database" << std::endl;
}
}
void show_latest_special_entry(const std::string& search) {
int32_t index = contacts.size() - 1;
while ( index >= 0 && contacts[index].get_relation() != search ) {
index--;
}
if ( index >= 0 ) {
std::cout << "The latest " << search << " entry is " + contacts[index].to_string() << std::endl;
} else {
std::cout << "There are currently no " << search << " entries" << std::endl;
}
}
void show_latest_friend_entry() {
show_latest_special_entry("Friend");
}
void show_latest_family_entry() {
show_latest_special_entry("Family");
}
void list_all_entries_by_age() {
if ( ! contacts.empty() ) {
std::vector<Contact> copy_contacts = contacts;
std::sort(copy_contacts.begin(), copy_contacts.end());
for ( const Contact& contact : copy_contacts ) {
std::cout << contact.to_string() << std::endl;
}
} else {
std::cout << "There are currently no entries in the database" << std::endl;
}
}
int main() {
read_file();
uint32_t choice = 0;
while ( choice != 6 ) {
std::cout << std::endl;
std::cout << " Menu " << std::endl;
std::cout << " 1: Add a new entry" << std::endl;
std::cout << " 2: Show latest entry" << std::endl;
std::cout << " 3: Show latest Friend entry" << std::endl;
std::cout << " 4: Show latest Family entry" << std::endl;
std::cout << " 5: List all entries by age" << std::endl;
std::cout << " 6: Close the program" << std::endl;
std::cout << std::endl;
std::cin >> choice;
switch ( choice ) {
case 1 : add_new_entry(); break;
case 2 : show_latest_entry(); break;
case 3 : show_latest_friend_entry(); break;
case 4 : show_latest_family_entry(); break;
case 5 : list_all_entries_by_age(); break;
case 6 : std::cout << "Program closed" << std::endl; break;
default : std::cout << "Please enter a number in the range 1..6" << std::endl; break;
}
}
}
</syntaxhighlight>
{{ out }}
<pre>
Menu
1: Add a new entry
2: Show latest entry
3: Show latest Friend entry
4: Show latest Family entry
5: List all entries by age
6: Close the program
1
Type the new entry, without inverted commas, in the format:
Name, Birth_Date, State, Relation, Email
Sally Whittaker, 1988-12-05, Illinios, Friend, sally@mail.com
The contact "Sally Whittaker, 1988-12-05, Illinios, Friend, sally@mail.com" has been added to the database
Menu
1: Add a new entry
2: Show latest entry
3: Show latest Friend entry
4: Show latest Family entry
5: List all entries by age
6: Close the program
1
Type the new entry, without inverted commas, in the format:
Name, Birth_Date, State, Relation, Email
Sandy Allen, 2002-0-09, Colorado, Friend, sandya@mail.com
The contact "Sandy Allen, 2002-0-09, Colorado, Friend, sandya@mail.com" has been added to the database
Menu
1: Add a new entry
2: Show latest entry
3: Show latest Friend entry
4: Show latest Family entry
5: List all entries by age
6: Close the program
5
Sandy Allen, 2002-0-09, Colorado, Friend, sandya@mail.com
Sally Whittaker, 1988-12-05, Illinios, Friend, sally@mail.com
Menu
1: Add a new entry
2: Show latest entry
3: Show latest Friend entry
4: Show latest Family entry
5: List all entries by age
6: Close the program
6
Program closed
</pre>
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