Splitting read file C++ - c++

Question

Lets start with that I have absolutely no experience with C++ , but I got this project to connect a POS with a verifone. We do not have the standard verifone SDK but something custom.
At fist I needed to prepair data to send to C++ and C++ will send it to the Verifone. This is where I am getting stuck, I have a .txt file, which I can read with C++ but now I need to split the data.
This is my current code:
#include "stdafx.h"
#include <sstream>
#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
string file_get_contents(const char *filename)
{
ifstream in(filename);
if (in.fail())
{
cerr << "File not found: " << filename << endl;
return "";
}
std::stringstream buffer;
buffer << in.rdbuf();
in.close();
return buffer.str();
}
int main(int argc, char **argv)
{
vector<string> strings;
string contents = file_get_contents("C:/wamp/www/cmd/config.txt");
string s;
while (contents, s, '||') {
cout << s << endl;
strings.push_back(s);
}
cout << s; // ECHO CONTENTS
std::cin.ignore(); // pause
return 0;
}
With this code my console just stays blank, no data is being displayed.
The full string I am splitting is:
"notepad://amount=10320.53||session_id=7946548443287465/"
The result that I want is to get an array that uses "amount" and "session_id" as keys and their values as value.
What is the best way of achieving this?
I used the following code to actually display the string in my console which was working:
int main(int argc, char **argv)
{
string contents = file_get_contents("config.txt");
cout << contents; // ECHO CONTENTS
std::cin.ignore(); // pause
return 0;
}

Answer 1

This shows how to use a regex to extract the information you want, there are a lot of online resources on how to read files properly so I left that part out.
#include <iostream>
#include <regex>
#include <unordered_map>
#include <string>
int main(int argc, char **argv)
{
std::regex pattern("amount=([[:digit:]\\.]*)\\|\\|session_id=([[:digit:]]*)");
std::smatch results;
std::unordered_map<std::string, std::string> data;
std::string contents = "notepad://amount=10320.53||session_id=7946548443287465/";
//string contents = file_get_contents("C:/wamp/www/cmd/file.txt");
if(std::regex_search(contents, results, pattern))
{
data["amount"] = results[1];
data["session_id"] = results[2];
}
std::cout << "Amount: " << data["amount"] << std::endl;
std::cout << "Seesion ID: " << data["session_id"] << std::endl;
return 0;
}