XML Parsing using Structures in C++ - c++

Question

I have tried to parse an xml file using tinyxml API in C++ through structure implementation, but my below code does not produce the result which i am expected. Below is the My code.
#include<iostream>
#include<list>
#include<string>
#include"tinyxml.h"
using namespace std;
struct accsys
{
string name;
string type;
float rate;
};
void parser(struct accsys acc)
{
list<accsys> l;
TiXmlDocument* doc= new TiXmlDocument();
doc->LoadFile("accountsys.xml");
TiXmlElement* root=doc->RootElement();
TiXmlElement* accountElement=root->FirstChildElement();
while(accountElement)
{
TiXmlElement* nameElement=accountElement->FirstChildElement();
acc.name=nameElement->GetText();
TiXmlElement* typeElement=nameElement->NextSiblingElement();
acc.type=typeElement->GetText();
TiXmlElement* rateElement=typeElement->NextSiblingElement();
acc.rate=atof(rateElement->GetText());
l.push_back(acc);
accountElement=accountElement->NextSiblingElement();
}
}
void display(struct accsys acc)
{
list<accsys> l;
list<accsys>::iterator i;
i=l.begin();
while(i!=l.end())
{
cout<<"name:"<<i->name<<endl;
cout<<"type:"<<i->type<<endl;
cout<<"rate:"<<i->rate<<endl;
i++;
}
}
int main()
{
struct accsys acc;
parser(acc);
display(acc);
return 0;
}
Can any one answer please!

Answer 1

Firstly, pass a reference to the std::list, not a empty struct, which won't live longer than in the function you make it. Neither can you make a list in one function and expect it to be there in another.
Fixed formatting, removed this ugly using namespace std;, and corrected your code. I assume this is what you want.
#include <iostream>
#include <list>
#include <string>
#include "tinyxml.h"
struct accsys
{
std::string name;
std::string type;
float rate;
};
void parser(std::list<accsys> &acc)
{
TiXmlDocument *doc = new TiXmlDocument();
doc->LoadFile("accountsys.xml");
TiXmlElement *root = doc->RootElement();
TiXmlElement *accountElement = root->FirstChildElement();
while (accountElement)
{
struct accsys structAcc;
TiXmlElement *nameElement = accountElement->FirstChildElement();
structAcc.name = nameElement->GetText();
TiXmlElement *typeElement = nameElement->NextSiblingElement();
structAcc.type = typeElement->GetText();
TiXmlElement *rateElement = typeElement->NextSiblingElement();
structAcc.rate = atof(rateElement->GetText());
acc.push_back(structAcc);
accountElement = accountElement->NextSiblingElement();
}
}
void display(std::list<accsys> &acc)
{
for (std::list<accsys>::iterator itr = acc.begin(); itr != acc.end(); ++itr)
{
std::cout << "name: " << itr->name << std::endl;
std::cout << "type: " << itr->type << std::endl;
std::cout << "rate: " << itr->rate << std::endl;
}
}
int main()
{
std::list<accsys> acc;
parser(acc);
display(acc);
return 0;
}

Answer 2

I can see at least 3 big errors in your code:
1) As marcinj has alrteady pointed out you are passing to your parser() function a copy of the struct accsys and whatever you fill in that structure you will never find it outside the function.
2) Again in parser you declare a list of your accsys struct which is local to the function, whatever you put in the list you will never see it outside the function, moreover in the while loop you keep overwriting values in your acc struct so even in the best case you would only see the last line of you xml file.
3) In the display function you pass an accsys struct to the function and the you forget it and try to print the content of a list of struct just created which is obviously empty.
So supposing the xml parser is correct your code would have to be more or less like this:
#include<iostream>
#include<list>
#include<string>
#include"tinyxml.h"
using namespace std;
struct accsys
{
string name;
string type;
float rate;
};
void parser(list<struct accsys *> &accList)
{
TiXmlDocument* doc= new TiXmlDocument();
doc->LoadFile("accountsys.xml");
TiXmlElement* root=doc->RootElement();
TiXmlElement* accountElement=root->FirstChildElement();
while(accountElement)
{
struct accsys *acc = new struct accsys;
TiXmlElement* nameElement=accountElement->FirstChildElement();
acc->name=nameElement->GetText();
TiXmlElement* typeElement=nameElement->NextSiblingElement();
acc->type=typeElement->GetText();
TiXmlElement* rateElement=typeElement->NextSiblingElement();
acc->rate=atof(rateElement->GetText());
l.push_back(acc);
accountElement=accountElement->NextSiblingElement();
}
}
void display(list<struct accsys *> &l)
{
list<struct accsys *>::iterator i;
i=l.begin();
while(i!=l.end())
{
cout<<"name:"<<i->name<<endl;
cout<<"type:"<<i->type<<endl;
cout<<"rate:"<<i->rate<<endl;
i++;
}
}
int main()
{
list <struct accsys *> acc;
parser(acc);
display(acc);
return 0;
}