The task is to read a configuration file in standard configuration file format,
and set variables accordingly.

For this task, we have a configuration file as follows:

# This is a configuration file in standard configuration file format
#
# Lines beginning with a hash or a semicolon are ignored by the application
# program. Blank lines are also ignored by the application program.

# This is the fullname parameter
FULLNAME Foo Barber

# This is a favourite fruit
FAVOURITEFRUIT banana

# This is a boolean that should be set
NEEDSPEELING

# This boolean is commented out
; SEEDSREMOVED

# Configuration option names are not case sensitive, but configuration parameter
# data is case sensitive and may be preserved by the application program.

# An optional equals sign can be used to separate configuration parameter data
# from the option name. This is dropped by the parser. 

# A configuration option may take multiple parameters separated by commas.
# Leading and trailing whitespace around parameter names and parameter data fields
# are ignored by the application program.

OTHERFAMILY Rhu Barber, Harry Barber



For the task we need to set four variables according to the configuration entries as follows:

fullname = Foo Barber
favouritefruit = banana
needspeeling = true
seedsremoved = false


We also have an option that contains multiple parameters. These may be stored in an array.

 otherfamily(1) = Rhu Barber
 otherfamily(2) = Harry Barber


Related tasks
 Update a configuration file


#include "stdafx.h"
#include <iostream>
#include <fstream>
#include <vector>
#include <string>
#include <boost/tokenizer.hpp>
#include <boost/algorithm/string/case_conv.hpp>
using namespace std;
using namespace boost;
 
typedef boost::tokenizer<boost::char_separator<char> > Tokenizer;
static const char_separator<char> sep(" ","#;,");
 
//Assume that the config file represent a struct containing all the parameters to load
struct configs{
	string fullname;
	string favoritefruit;
	bool needspelling;
	bool seedsremoved;
	vector<string> otherfamily;
} conf;
 
void parseLine(const string &line, configs &conf)
{
	if (line[0] == '#' || line.empty())
		return;
	Tokenizer tokenizer(line, sep);
	vector<string> tokens;
	for (Tokenizer::iterator iter = tokenizer.begin(); iter != tokenizer.end(); iter++)
		tokens.push_back(*iter);
	if (tokens[0] == ";"){
		algorithm::to_lower(tokens[1]);
		if (tokens[1] == "needspeeling")
			conf.needspelling = false;
		if (tokens[1] == "seedsremoved")
			conf.seedsremoved = false;
	}
	algorithm::to_lower(tokens[0]);
	if (tokens[0] == "needspeeling")
		conf.needspelling = true;
	if (tokens[0] == "seedsremoved")
		conf.seedsremoved = true;
	if (tokens[0] == "fullname"){
		for (unsigned int i=1; i<tokens.size(); i++)
			conf.fullname += tokens[i] + " ";
		conf.fullname.erase(conf.fullname.size() -1, 1);
	}
	if (tokens[0] == "favouritefruit") 
		for (unsigned int i=1; i<tokens.size(); i++)
			conf.favoritefruit += tokens[i];
	if (tokens[0] == "otherfamily"){
		unsigned int i=1;
		string tmp;
		while (i<=tokens.size()){		
			if ( i == tokens.size() || tokens[i] ==","){
				tmp.erase(tmp.size()-1, 1);
				conf.otherfamily.push_back(tmp);
				tmp = "";
				i++;
			}
			else{
				tmp += tokens[i];
				tmp += " ";
				i++;
			}
		}
	}
}
 
int _tmain(int argc, TCHAR* argv[])
{
	if (argc != 2)
	{
		wstring tmp = argv[0];
		wcout << L"Usage: " << tmp << L" <configfile.ini>" << endl;
		return -1;
	}
	ifstream file (argv[1]);
 
	if (file.is_open())
		while(file.good())
		{
			char line[255];
			file.getline(line, 255);
			string linestring(line);
			parseLine(linestring, conf);
		}
	else
	{
		cout << "Unable to open the file" << endl;
		return -2;
	}
 
	cout << "Fullname= " << conf.fullname << endl;
	cout << "Favorite Fruit= " << conf.favoritefruit << endl;
	cout << "Need Spelling= " << (conf.needspelling?"True":"False") << endl;
	cout << "Seed Removed= " << (conf.seedsremoved?"True":"False") << endl;
	string otherFamily;
	for (unsigned int i = 0; i < conf.otherfamily.size(); i++)
		otherFamily += conf.otherfamily[i] + ", ";
	otherFamily.erase(otherFamily.size()-2, 2);
	cout << "Other Family= " << otherFamily << endl;
 
	return 0;
}
 