Forum: Vektorer

#include <string>
#include <vector>
#include <iostream>
#include <limits>
#include <fstream>
 
struct person;
struct filperson {
	person& p;
	filperson(person& _p): p(_p) {}
};
struct person {
	std::string namn, adress, telefon;
	void fraga(std::istream& ist, std::ostream& ost);
};
 
void person::fraga(std::istream& ist, std::ostream& ost)
{
	std::string s;
	ost << "Namn [" << namn << "]: ";
	std::getline(ist, s);
	if (!s.empty()) namn = s;
 
	ost << "Adress [" << adress << "]: ";
	std::getline(ist, s);
	if (!s.empty()) adress = s;
 
	ost << "Telefon [" << telefon << "]: ";
	std::getline(ist, s);
	if (!s.empty()) telefon = s;
}
 
std::ostream& operator << (std::ostream& ost, person& p)
{
	ost << "   Namn: " << p.namn << std::endl;
	ost << " Adress: " << p.adress << std::endl;
	ost << "Telefon: " << p.telefon << std::endl;
	return ost;
}
 
std::istream& operator >> (std::istream& ist, filperson& fp)
{
	std::getline(ist, fp.p.namn);
	std::getline(ist, fp.p.adress);
	std::getline(ist, fp.p.telefon);
	return ist;
}
 
std::ostream& operator << (std::ostream& ost, filperson& fp)
{
	ost << fp.p.namn << std::endl;
	ost << fp.p.adress << std::endl;
	ost << fp.p.telefon << std::endl;
	return ost;
}
 
std::vector<person> db;
 
void las_fil(std::istream& f) {
	person p;
	filperson fp(p);
	while (f >> fp) {
		db.push_back(p);
	}
}
void las_fil(const char *f) {
	std::ifstream ifs(f);
	return las_fil(ifs);
}
 
void skriv_fil(std::ostream& f) {
	for (std::vector<person>::iterator i = db.begin(); i != db.end(); ++i) {
		filperson fp(*i);
		f << fp;
	}
}
void skriv_fil(const char *f) {
	std::ofstream ofs(f);
	return skriv_fil(ofs);
}
 
int las_nummer() {
	int i;
	bool ok;
	do {
		ok = (std::cin >> i);
		std::cin.clear();
		std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
	} while (!ok);
	return i;
}
 
int main() {
	las_fil("personer.txt");
	int menu;
	do {
		do {
			std::cout << "0. sluta" << std::endl;
			std::cout << "1. visa alla" << std::endl;
			std::cout << "2. skriva ny" << std::endl;
			std::cout << "3. ändra" << std::endl;
			std::cout << "4. ta bort" << std::endl;
			std::cout << "välja: ";
			menu = las_nummer();
		} while (menu < 0 || 4 < menu);
		switch (menu) {
			case 1: {
				for (std::vector<person>::size_type i = 0; i < db.size(); ++i) {
					std::cout << i << ".\n" << db[i] << std::endl;
				}
				break;
			}
			case 2: {
				person p;
				p.fraga(std::cin, std::cout);
				db.push_back(p);
				break;
			}
			case 3: {
				if (db.empty()) {
					std::cout << "Det finns ju inga!" << std::endl;
					break;
				}
				std::cout << "Vilken ska du ändra?" << std::endl << "nummer: ";
				std::vector<person>::size_type i = las_nummer();
				if (i < 0 || db.size() <= i) {
					std::cout << "Det finns inte person " << i << "!" << std::endl;
					break;
				}
				db[i].fraga(std::cin, std::cout);
				break;
			}
			case 4: {
				if (db.empty()) {
					std::cout << "Det finns ju inga!" << std::endl;
					break;
				}
				std::cout << "Vilken ska du ta bort?" << std::endl << "nummer: ";
				std::vector<person>::size_type i = las_nummer();
				if (i < 0 || db.size() <= i) {
					std::cout << "Det finns inte person " << i << "!" << std::endl;
					break;
				}
				db.erase(db.begin() + i);
				break;
			}
		}
	} while (menu != 0);
	skriv_fil("personer.txt");
}