Conditions and files - c++

Question

class Client
{
public:
Client(int id, string title, int age):
~Client();
void addTW(int id, string title, int age);
int getID() const {return id;}
string getTitle() const {return title;}
int getAge() const {return age;}
private:
int id;
string title;
int age;
};
I have two functions:
load(), which is loading input .txt file - file's having titles of movies and age you need to have in order to watch the movie (e.x. Pulp Fiction - 16) and
addTW(int id, string title, int age), which adds Movies.
So, while adding a movie, you need to type id, title and age. I want to make that you cannot add movie if you're under a certain age (e.x. 16 or whatever). Age must be re-added from the .txt file. Basically age in connected with and only title.
I've never used .txt files. So I have no idea how to start.
#include <fstream>
void Client::addTW(int id, string title, int age)
{
int i, n = tw.size();
for(i = 0;i<n;i++)
{
ToWatch* newTW = new ToWatch(id, title, age);
tw.push_back(newTW);
return;
}
}
void Client::load()
{
ifstream input;
input.open("input.txt");
if(input.fail())
{ cout<<"Failure"<<endl;}
else
{
string s;
while(input>>s)
{
cout<<s<<" ";
}
}
input.close();
}

Answer 1

I am not sure, if the design of your class is OK. This you can find out by yourself.
I can help you with reading the file and extracting the age for a given title:
Please see:
#include <iostream>
#include <fstream>
#include <string>
unsigned int getAgeFromFile(const std::string& title) {
// We set a default age of 0. So, if we cannot find the title in the list, then everybody can look it
unsigned int resultingAge{ 0 };
// Define an ifstream variable. Use its constructor, to open the file, then check, if open was ok
if (std::ifstream fileMovies("input.txt"); fileMovies) {
// Read all lines in the text file in a loop with std::getline. std::getline will return false,
// if we are at end-of-file or in case of some other error. Then the loop will stop
for (std::string line{}; std::getline(fileMovies, line); ) {
// So, now we have a line from the file in tour "line" variable.
// Check, if the searched title is in it
if (line.find(title) != std::string::npos) {
// Ok, we found the title in this line. Now, we need to extract the age.
// It is at the end of the line and separated by a space. So, search from the end of the line for a space
if (size_t pos{ line.rfind(' ') }; pos != std::string::npos) {
// We found a space. Now, convert the number.
resultingAge = std::stoul(line.substr(pos));
}
}
}
}
// return result or default value, if not found
return resultingAge;
}
In your addTW function you need to insert one line before the
push_back.
if (age > getAgeFromFile(title))
Hope this helps.
Compiled and tested with VS2019 and C++17