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Hey,
I'm a beginning C++ programmer and I'm writing a console file-search application that uses a DataBase with a list of files (like locate from the linux shell). Below is the sourcecode that I've written so far. I'm posting it here because I don't know any good programmers myself and I would really like to get some tips and comments to push me in the right direction.

Besides that, I've also got a few specific questions:

1)
The inline function UnDefBit sets a bit to zero by doing the following:
lineofbits = ((2^32)-1 - 2^bitnumber) AND lineofbits.
I was wondering if there is an easier way to do this because this seems kind of time-consuming to me, and I'd rather not load the math.h library.

2)
Someone told me that I should use a DWORD for storing rows of bits. Why should I use a DWORD instead of a long int?

Code:

#include <windows.h>
#include <iostream.h>
#include <math.h>

DWORD OptionFlags = 0;

inline bool BitTrue(DWORD a, DWORD b) { return (a & (1 << b)) ? true : false; } //Is bit 1?
inline void DefBit(DWORD &a, DWORD b) { a = (a | (1 <<  b)); } //define bit
inline void UnDefBit(DWORD &a, DWORD b) { a = DWORD(4294967295 - pow(2, b)) & a; } //undefine bit


DWORD LogicDrives(bool HDsOnly) //All Logical drives or Harddisks only
{	
	DWORD DriveList = GetLogicalDrives();
	
	if (HDsOnly)
	{
		char DriveCheck[4] = "*:\\";
		for (int a = 0; a < 26; a++)
		{	
			if (BitTrue(DriveList, a)) 
			{
				DriveCheck[0]= 'a'+a;
				UnDefBit(DriveList, a);
				if (GetDriveType(DriveCheck)==3) DefBit(DriveList, a); //Check if it's a HD
			}
		}
	}
	
	return DriveList;
}


DWORD DrivesFromArgs(int argc, char *argv[]) //Drives from arguments
{
	DWORD DriveList = 0;
	char DrivesString[26];

	for (int a = 1; a < argc; a++) //Get DrivesString from arguments
	{
			if (argv[a][0] == '/' && argv[a][1] == 'd')
			{
					strcpy(DrivesString, argv[a + 1]);
					break;
			}
	}

	for (a = 0; a < 26; a++) //Create DriveList from DrivesString[]
	{
			if (DrivesString[a] >= 'a' && DrivesString[a] <= 'z') DefBit(DriveList, DrivesString[a] - 'a');
			else break;
	}

	return DriveList;
}


DWORD Options(int argc, char *argv[]) //Get Options from arguments
{	
	DWORD Flags=0;
	for(int a = 1; a < argc; a++)
	{
		if (argv[a][0] == '/')
		{
			switch (argv[a][1])
				{
					case 'c': DefBit(Flags, 0); break; //Create DB
					case 'v': DefBit(Flags, 1); break; //Verbose mode
					case 'd': DefBit(Flags, 2); break; //Specified drives in args
					case 'a': DefBit(Flags, 3); break; //All logical drives
				}
		}
	}
	return Flags;
}


void Say(int LineNum, int a=0, DWORD Flags=0) //Output a line
{
	int b = 0;

	switch (LineNum) //will always be said
	{
		case 0: cout << "Start of program" << endl; return;
		case 1: cout << "End of program" << endl; return;
	}
	
	
	if (BitTrue(OptionFlags, 1)) //will only be said in verbose mode
	{
		switch (LineNum)
		{
			case 100: cout << a << " arguments: "; for(;b < 10;b++) cout << BitTrue(Flags, b); cout << endl; return;
			case 101: cout << "Creating database" << endl; return;
			case 102: cout << "Drives to index: "; for(;b < 26;b++) cout << BitTrue(Flags, b); cout << endl; return;
		}
	}
}


void CreateDatabase(int argc, char *argv[]) //Creates a database
{
	Say(101);
	DWORD DrivesToIndex;
		
	if (BitTrue(OptionFlags, 2)) DrivesToIndex = DrivesFromArgs(argc, argv); //Get drives from arguments
	else if (BitTrue(OptionFlags, 3)) DrivesToIndex = LogicDrives(false); //Do All logic drives
	else DrivesToIndex = LogicDrives(true); //Do all HDs
	
	Say(102,0,DrivesToIndex);
}


int main(int argc, char *argv[]) //main
{
	Say(0);	
	OptionFlags = Options(argc, argv); //get options
	Say(100, argc-1, OptionFlags);
	if (BitTrue(OptionFlags, 0)) CreateDatabase(argc, argv);
	Say(1);
	return 0;
}

Thanks for the help!

Add another function

Code:

inline DWORD Bit(pos) { return 1ul << pos; }                // A bit in the right pos
inline bool BitTrue(DWORD a, DWORD b) { return (a & Bit(b)) != 0; } //Is bit 1?
inline void DefBit(DWORD &a, DWORD b) { a |= Bit(b); }      //define bit
inline void UnDefBit(DWORD &a, DWORD b) { a &= ~Bit(b); }   //undefine bit

> Someone told me that I should use a DWORD for storing rows of bits. Why should I use a DWORD instead of a long int?
Except DWORD is currently specified in windows.h (which not everyone has)

Besides, its a rather generic type. You would be better with say
typedef unsigned long bits_t;
Which conveys a bit more meaning for what is going on, and is more portable to other platforms.

Man I feel stupid about my way of writing down a &= ~Bit(b)

thanks...