Beginner help needed

[hammb]

I am new to c++ (Visual C++ 6.0) and I am having some trouble getting this code to work properly. I come from a very different style of coding which is nothing like c or c++. Please help me get this code working properly. This is not for a project or program I am just trying to ensure I know what I am doing before I actually write a usefull program (long ways away I know)

Here is the code that I would like to execute:

#include <windows.h>
#include <stdio.h>
#include <iostream.h>
#include <String>

using namespace std;

int test();
bool PathExists(char pathtocheck[50]);


int test()
{
char i;
for (i='A'; i='Z'; i++)
{
if(GetDriveType (i) == DRIVE_FIXED)
{
if (PathExists(i && ":\\FOLDER PATH") == 1)
{
//do something if true
//not concerned about this code
}
}
}
return 0;
}

And here are the error messages


Compiling...
EraseTest.cpp
...\EraseTest.c pp(69) : error C2664: 'GetDriveTypeA' : cannot convert parameter 1 from 'char' to 'const char *'
Conversion from integral type to pointer type requires reinterpret_cas t, C-style cast or function-style cast
...\EraseTest.c pp(71) : error C2664: 'PathExists' : cannot convert parameter 1 from 'bool' to 'char []'
Conversion from integral type to pointer type requires reinterpret_cas t, C-style cast or function-style cast
Error executing cl.exe.

[hammb]

the && is just in there because I dont know what to put there...

thanks

[Banfa]

for (i='A'; i='Z'; i++)

You need to look up the difference between assignment = and conditional equal to ==. This for loop assigns the value 'A' to i, then it assigns the value 'Z' to i since 'Z' != 0 it executes the loop then it increments i then it assigns the value 'Z' to i again. It would run forever.



if(GetDriveType (i) == DRIVE_FIXED)

EraseTest.cpp
...\EraseTest.c pp(69) : error C2664: 'GetDriveTypeA' : cannot convert parameter 1 from 'char' to 'const char *'

GetDriveType takes a parameter of type const char * (typedef'd to LPCSTR) however you have tried to pass it a parameter of type char. It is expecting a string which is an array of printable characters followed by a terminating 0 character. 'A' is a character constant but "A" is a string where the first and only character is an 'A'. However "A" is 2 characters long because it has a terminating 0 (NULL) character.

GetDriveType is expecting a string.

Note the error is on GetDriveTypeA because GetDriveType is a #defined symbol that is defined to point either at the narrow (single byte) character function GetDriveTypeA or the wide (multi-byte) character function GetDriveTypeW. This is a common feature in Windows.



if (PathExists(i && ":\\FOLDER PATH") == 1)

The reason you do not know what you put in place of the && is because there is nothing you can put in place there to concatenate a char (i) and a string literal.

To concatenate 2 strings you would have to use a function like strcat or a class like string

[hammb]

for (i='A'; i='Z'; i++)

* changed to:

for (i = 'A'; i <= 'Z'; i++)

* if(GetDriveType (i) == DRIVE_FIXED)

can you tell me how to get the value from i above into this function properly


if (PathExists(i && ":\\FOLDER PATH") == 1)

The reason you do not know what you put in place of the && is because there is nothing you can put in place there to concatenate a char (i) and a string literal.

To concatenate 2 strings you would have to use a function like strcat or a class like string

*Please provide an example.
*Here is what I tried:

char strcpy;
strcpy (str, c);
* and it doesn't work.

[sicarie]

for (i='A'; i='Z'; i++)

* changed to:

for (i = 'A'; i <= 'Z'; i++)

* if(GetDriveType (i) == DRIVE_FIXED)

can you tell me how to get the value from i above into this function properly


if (PathExists(i && ":\\FOLDER PATH") == 1)

The reason you do not know what you put in place of the && is because there is nothing you can put in place there to concatenate a char (i) and a string literal.

To concatenate 2 strings you would have to use a function like strcat or a class like string

*Please provide an example.
*Here is what I tried:

char strcpy;
strcpy (str, c);
* and it doesn't work.

If you read Banfa's post again, you will see he suggested strcat, not strcpy (which copies one into the other, it does not combine them, which is what strcat does). Reread his post and links, and try again. You have the right idea (I think), just keep at it.

[hammb]

Almost there...

Thanks a million.. I have already learned so much from this post.
Here is what I have now.. The last thing I need help with is assigning the string pointer value.
--------------------------------------------------------------------------------------------------------
char i;
string iS;
string iT;
string IQ;
char* p_IQ;

for (i='A'; i<='Z'; i++)
{
iS = ":\\";
iT = i;
IQ = iT + iS;

//p_IQ = &IQ; //This doesnt work
//strcpy(p_IQ, IQ); //This doesnt work either

if(GetDriveType (p_IQ) == DRIVE_FIXED)
{//DO SOMETHING IF IT WORKS}
}

[hammb]

for this line...

char* p_IQ;

I also tried string* p_IQ which doest work either

[Banfa]

there is a member methof of string, string::c_str() which returns a const char * pointer to the data in the string.

However you can not just copy this to p_IQ because you have not allocated any data to p_IQ (it is unitialised) so you would cause a memory exception.

[hammb]

so here it is.. Works perfectly. I want to thank you guys. I really appreciate the help.

{
char i;
string iS;
string iT;
string IQ;
char* p_IQ;

for (i='A'; i<='Z'; i++)
{
iS = ":\\";
iT = i;

IQ = iT + iS;

p_IQ = new char[IQ.length() + 1];
strcpy(p_IQ, IQ.c_str());

if(GetDriveType (p_IQ) == DRIVE_FIXED)
{
cout << IQ << "is a fixed drive\n";
}}}