Working with structs? - c++

Question

I'm having trouble working with strings (char*) in structs. I can't seem to call the right data I want too.
Under processFile it shows the struct member correctly; under main it does not.
Here is my code:
#include <iostream>
#include <io.h>
#include <string>
#include "dirent.h"
#include "Stream.h"
#include "Compression.h"
#include "Definitions.h"
using namespace std;
using namespace System::IO;
using namespace System::Funcs;
bool isRawfile(char* ext);
void ProcessDirectory(string directory);
void ProcessFile(char* file);
void ProcessEntity(struct dirent* entity);
typedef struct
{
char *name;
int usize;
int csize;
BYTE *data;
} rawfile;
string path = "";
string source;
int numrawfiles = 0, numstringtables = 0;
rawfile *rawfiles = new rawfile[0x400];
FILE * zone = fopen( "C:\\Users\\jake\\Desktop\\patch_mp.zone" , "wb" );
int main(int argc, char **args)
{
if(args[1] != NULL)
{
source = string(args[1]) + "\\"; //maybe move under else here..
if(strchr(args[1], '.') != NULL)
{
cout<<"Unable to compile files, please drag a folder to compile."<<endl;
cin.get();
return 0;
}
else
{
int header[] = {1,0,0x3B4,0,0,0,1,0,0x1000,0,0,0,-1};
for(int i=0; i<13; i++)
fwrite(Converter::Int32ToBytes(header[i]), 1 , 4 , zone );
ProcessDirectory(args[1]);
for(int i=0; i<numrawfiles; i++)
cout<<"Name: "<<rawfiles[i].name<<" Length: "<< rawfiles[i].usize << " - in main()"<<endl;
fclose(zone);
}
}
else
{
cout<<"No folder selected to compile. Press any Key to quit."<<endl;
cin.get();
return 0;
}
cin.get();
return 0;
}
void ProcessDirectory(string directory)
{
string dirToOpen = path + directory;
auto dir = opendir(dirToOpen.c_str());
path = dirToOpen + "\\";
if(NULL == dir)
{
cout << "could not open directory: " << dirToOpen.c_str() << endl;
return;
}
auto entity = readdir(dir);
while(entity != NULL)
{
ProcessEntity(entity);
entity = readdir(dir);
}
path.resize(path.length() - 1 - directory.length());
closedir(dir);
}
void ProcessEntity(struct dirent* entity)
{
if(entity->d_type == DT_DIR)
{
if(entity->d_name[0] == '.')
return;
ProcessDirectory(string(entity->d_name));
return;
}
if(entity->d_type == DT_REG)
{
string fullpath = path + entity->d_name;
ProcessFile(const_cast<char *>(fullpath.c_str()));
return;
}
cout << "Not a file or directory: " << entity->d_name << endl;
}
void ProcessFile(char* file)
{
char* extension = strrchr(file, '.');
if(isRawfile(extension))
{
rawfile raw;
raw.name = (char *)&file[source.length()];
raw.usize = File::getFileSize(file);
rawfiles[numrawfiles] = raw;
cout<<"Name: "<<rawfiles[numrawfiles].name<<" Length: "<< raw.usize << " - in ProcessFile()"<<endl;
fwrite(Converter::Int32ToBytes(0x23),1,4,zone);
fwrite(Converter::Int32ToBytes(-1),1,4,zone);
numrawfiles++;
}
}
bool isRawfile(char* ext)
{
char *exts[11] = {".gsc",".cfg",".txt",".news",".png",".vision",".rmb",".script",".arena",".atr",".csc"};
for(int i=0; i<10; i++)
if(strncmp(ext,exts[i],strlen(exts[i]))==0)
return true;
return false;
}
Here is an example picture:
What am I doing wrong?

Answer 1

Save yourself a lot of trouble by using an std::string:
#include <string>
struct thing
{
std::string name;
int age;
};
You can also avoid the dynamically allocated array:
#include <vector>
std::vector<thing> things(3);

Answer 2

You are outputting the memory address of "Ben" instead of the actual String. You should use
cout << things[1]->name << endl;
which is syntactic sugar for
cout << (*things[1]).name << endl;

Answer 3

To add to what scd said, you are not successfully dereferencing the name member. When you try and operate on things[1].name you are operating on a pointer, which is simply a memory location.
This is one of the trickiest things when learning to use pointers. Here is some more reading on the dereference operator, and syntax hints.
http://en.wikipedia.org/wiki/Dereference_operator#Other_syntax
Edit:
After compiling myself, I realized that I was on the wrong track with this one, and that std::cout will correctly handle the char pointer. You should be able to solve this with your code, just ensure that you give your struct array a size.
This worked for me:
#include <iostream>
#define MAXSIZE 3
typedef struct
{
char* name;
int age;
}Thing;
Thing *things = new Thing[MAXSIZE];
int _tmain(int argc, _TCHAR* argv[])
{
char* names[MAXSIZE] = { "Alice", "Ben", "Carlos" };
int ages[MAXSIZE] = { 24, 25, 26 };
for(int i=0; i<MAXSIZE; i++)
{
things[i].name = names[i];
things[i].age = ages[i];
}
std::cout << things[1].name << std::endl;
return 0;
}