contact list

phonedb.cpp

#include <iostream>
#include <fstream>
#include <string>
#include <vector>

using namespace std;

class Database {
	fstream table;
public:
	static vector<string> record2vector(string s)
	{
		vector<string> out;

		int pos = 0;
		string token;
		while ((pos = s.find(",")) != string::npos) {
			token = s.substr(0, pos);
			out.push_back(token);
			s.erase(0, pos + 1);
		}
		out.push_back(s);

		return out;
	}

	void reload()
	{
		table.close();
		table.open(tablename, ios::out|ios::in|ios::app);
	}

	string tablename;
	int init(string tblname)
	{
		tablename = tblname+".csv";
		table.open(tablename, ios::out|ios::in|ios::app);
		if (!table)
			return -1;
		return 0;
	}

	void create(string record)
	{
		table.seekp(ios::end);
		table << record << endl;
		table.flush();
	}

	vector<string> select(int index, string value)
	{
		vector<string> out, vrec;

		table.seekg(ios::beg);

		string rec;

		while(1) {
			table >> rec;
			if (table.eof())
				break;
			vrec = record2vector(rec);

			if (vrec[index] == value || index < 0)
				out.push_back(rec);
		}

		reload();
		return out;
	}

	int update(int index, string value, string record)
	{
		string text;
		table.seekg(ios::beg);

		string line;
		vector<string> vrec;
		while(1) {
			table >> line;
			if(table.eof())
				break;

			vrec = record2vector(line);
			if (vrec[index] == value)
				line = record;

			text.append(line+"\n");
		}

		remove(tablename.c_str());
		reload();
		table << text;
		table.flush();
		return 0;
	}


	int del(int index, string value)
	{
		string text;
		table.seekg(ios::beg);

		string line;
		vector<string> vrec;
		while(1) {
			table >> line;
			if(table.eof())
				break;

			vrec = record2vector(line);
			if (vrec[index] != value)
				text.append(line+"\n");
		}

		remove(tablename.c_str());
		reload();
		table << text;
		table.flush();
		return 0;
	}

	~Database()
	{
		table.close();
	}
};

enum {
	/* user model */
	FUSER_USERNAME = 0,
	FUSER_PHONE,
};

Database users;

int main()
{
	users.init("users");

	while (1) {
		char opt;
		int index;
		string record, srchval;

		vector<string> vrecs;

		cout << "[1] Create user" << endl
			 << "[2] Search user" << endl
			 << "[3] Update user" << endl
			 << "[4] Delete user" << endl
			 << "[e] Exit" << endl << endl
			 << "Choose option: ";
		cin >> opt;

		switch (opt)
		{
		case '1':
			cout << "Enter (Format: username,phone): ";
			cin >> record;

			users.create(record);
			break;

		case '2':
			cout << "Enter search index [username=0,phone=1] (-1 for show all): ";
			cin >> index;
			if (index >= 0) {
				cout << "Enter search value: ";
				cin >> record;
			}

			cout << "username,phone" << endl;
			vrecs = users.select(index, record);
			for (auto &&r : vrecs) {
				cout << r << endl;
			}
			break;

		case '3':
			cout << "Enter search index [username=0,phone=1]: ";
			cin >> index;
			cout << "Enter search value: ";
			cin >> srchval;
			cout << "Enter new data (Format: username,phone): ";
			cin >> record;

			users.update(index, srchval, record);
			break;

		case '4':
			cout << "Enter search index [username=0,phone=1]: ";
			cin >> index;
			cout << "Enter search value: ";
			cin >> srchval;

			users.del(index, srchval);
			break;

		case 'e':
			return 0;

		default:
			break;
		}
	}

	return 0;
}