Problems formatting arrays and strings in C++ - c++

Question

I'm having a simple problem that's been driving me nuts all day. I am trying to open a file on the current user's Desktop without knowing the current user's name.
The idea is that I would use the GetCurrentUser call to the API to get the user name. Then format a string to give the full path directory, and pass that variable into fopen to open the file. Here is the code I'm working on, I get no compiler errors and it compiles fine but nothing writes to the file.
int main() {
char pathName[200]; // declaring arrays
char userName[100];
DWORD userNameSize = sizeof(userName); // storage for user name
if (!GetUserName(userName, &userNameSize)) { cout << "user not found"; }
else { cout "hello" << userName;} // error checking
// format for Windows 7 desktop
sprintf(pathName, "\"C:\\Users\\%s\\Desktop\\text.txt\"", userName);
cout << pathName << "\n"; // confirms correct location
const char* fileLocation = pathName; // pointer to full path to pass into fputs
const char* test = "test"; // test information to write to file to confirm
FILE *f = fopen(fileLocation,"a+"); // open file in append mode
fputs(test, f); // write to file
fclose(f); // flush and exit
return 0;
}
Maybe I need to use a different call to format the string? Or declare fileLocation as a different variable type?
I'm fairly new to C++ and would appreciate any tips that would help me to be able to open a file on the current user's Desktop. Thanks.
EDIT IN RESPONSE TO JERRY'S ADVICE:
This is what my latest comment was referring to:
#include <iostream>
#include <cstring>
#include <string>
#include <conio.h>
using namespace std;
string location ("C:\\Users\\testuser\\Desktop\\log.dat");
char cstr = char* [location.size()]; //This is a problematic line
strcpy (cstr, location.c_str());
void write(const char* c)
{
const char* fileLocation = cstr;
//const char* fileLocation = g_pathName;
FILE *f = fopen(fileLocation,"a+"); // This is the problematic line right here.
if(f!=NULL)
{
fputs(c,f); // append to end of file
fclose(f); // save so no entries are lost without being flushed
}
}
int main ()
{
write("test");
cout << "done";
_getch();
return 0;
}

Answer 1

You have a missing semicolon at line 9 where it says:
...{ cout << "user not found" }...
Semicolons are not optional in C++, you need them for a working program. Also, as stated in the comments, you do not need quotes around the name of the file.

Answer 2

I'd use SHGetSpecialFolderPath from shlobj.h:
const char *szFileName = "text.txt";
const char *szContent = "test string";
char szPath[_MAX_PATH];
SHGetSpecialFolderPath(NULL, szPath, CSIDL_DESKTOPDIRECTORY, FALSE);
strcat(szPath, "\\");
strcat(szPath, szFileName);
FILE *pFile = fopen(szPath, "a+");
if(pFile != NULL)
{
fputs(szContent, pFile);
fclose(pFile);
}

Answer 3

I would use SHGetKnownFolderPath with FOLDERID_Desktop to get the path to the desktop, then add a file name to the end. You also almost certainly want to do the manipulation on std::strings, then when you've created the full name, use the .c_str member function to retrieve the name as a C-style string. Unless you have a really specific reason to do otherwise, you're probably better off using a std::ofstream instead of a C-style FILE * as well (and in that case if your compiler is current, you can probably pass the std::string object directly as the name).
Edit: some quick demo code creating and writing to a file on the user's desktop:
#include <windows.h>
#include <Shlobj.h>
#include <objbase.h>
#include <string>
#include <fstream>
#pragma comment(lib, "ole32.lib")
#pragma comment(lib, "shell32.lib")
std::string GetKnownFolderPath(REFKNOWNFOLDERID f) {
PWSTR sys_path;
SHGetKnownFolderPath(f, 0, NULL, &sys_path);
DWORD size = WideCharToMultiByte(CP_ACP, 0, sys_path, -1, 0, 0, NULL, NULL);
std::string path(size, ' ');
WideCharToMultiByte(CP_ACP, 0, sys_path, -1, &path[0], size, NULL, NULL);
// We're finished with the string the system allocated:
CoTaskMemFree(sys_path);
// WideCharToMultiByte leaves space for a NUL terminator we don't need
path.resize(path.size()-1);
return path;
}
int main() {
std::string path(GetKnownFolderPath(FOLDERID_Desktop));
path += "\\test.txt";
std::ofstream test(path.c_str());
test << "This is a test";
return 0;
}