FILE *fp;
fp = fopen("sound.wav","rb);
if (fp)
{
BYTE id[4]; //four bytes to hold 'RIFF'
DWORD size; //32 bit value to hold file size
fread(id,sizeof(BYTE),4,fp); //read in first four bytes
if (!strcmp(id,"RIFF"))
{ //we had 'RIFF' let's continue
fread(size,sizeof(DWORD),1,fp);
//read in 32bit size value
}
} C++: The BYTE Class?
Author
Hi,
I'm learning how to read wave files with IOStreams and on the page i found, the author mentions nothing of the BYTE class/keyword/thing he's using.
BYTE and DWORD are Win32 types, defined in (some file included by) windows.h. A quick MSDN search should give you precise definitions.
This code has nothing to do with iostreams.
Judging by his use of BYTE and DWORD, I suspect that he is using the windows data types.
Judging by his use of BYTE and DWORD, I suspect that he is using the windows data types.
Author
Hmm,
Everyrhings in J#. Gonna use my actual MSDN help browser from visual studio and filter out the languages.
Everyrhings in J#. Gonna use my actual MSDN help browser from visual studio and filter out the languages.
Author
Quote:Original post by ToohrVyk
This code has nothing to do with iostreams.
Oh, isn't FILE a part of iostrams?
anyway, looks like i can't find anything useful(why am i not suprised). guess this is gonna be one of those "just know that it works, learn it later" things.
thanks for trying guys. :)
Quote:Oh, isn't FILE a part of iostrams?No, FILE is part of the C standard library, while the stream classes are part of the C++ standard library (of course the latter is part of the former, more or less, but you know what I mean).
Basically, you're writing Windows-specific C code. I don't know what your objectives are exactly, but I would recommend taking some time to become familiar with C++, as it will make your life much easier (compared to C, that is). (There are still a lot of tutorials floating around on the net that are either pure C or 'C++ but not really', so it's easy to get misled when looking for good references on this subject.)
Also, if you're interested in writing portable code, a good first step would be replace BYTE and DWORD with their C/C++ equivalents, char (probably unsigned) and... Well, there isn't a built-in primitive type in C++ (at this time) that's guaranteed to be 32 bits wide, but you can use the typedefs (uint32 or whatever) provided in newer versions of the C standard (?) or in the Boost libraries.
Author
omfg duh!!!
i could just open up visual studio(resource hog) instead of codeblock and intellisense would probably give me good info on it!!!
i could just open up visual studio(resource hog) instead of codeblock and intellisense would probably give me good info on it!!!
Oh, and you might consider adding an HTML 'horizontal rule' at the top of your signature - as is, it kind of looks like you're ending every single post with a quip about leaving the beginners' forum, which is kind of strange :)
Author
Quote:Original post by jyk
Oh, and you might consider adding an HTML 'horizontal rule' at the top of your signature - as is, it kind of looks like you're ending every single post with a quip about leaving the beginners' forum, which is kind of strange :)
hehe my bad.
another thing. i'm tinking i'm calling the wrong BYTE here. cause i'm getting an error telling me i need to perform a typecast.
example code:
FILE *fp; fp = fopen("sound.wav","rb"); if (fp) { BYTE id[4]; //four bytes to hold 'RIFF' DWORD size; //32 bit value to hold file size fread(id,sizeof(BYTE),4,fp); //read in first four bytes if (!strcmp(id,"RIFF")) { //we had 'RIFF' let's continue fread(size,sizeof(DWORD),1,fp); //read in 32bit size value } } and here's my version of the code:
#include <stdio.h>#include <windows.h>FILE * fp;int main(){ fp = fopen("sound.wav","rb"); if (fp) { BYTE id[4]; //four bytes to hold 'RIFF' DWORD size; //32 bit value to hold file size fread(id, sizeof(BYTE),4,fp); //rean in first four bytes if (!strcmp(id, "RIFF")) {//we had 'RIFF' let's continue fread(size, sizeof(DWORD), 1, fp); //read in 32bit size value } } return 0;}
His code is wrong. You can't use strcmp for two reasons:
1. You're comparing unsigned chars (Which is how a BYTE is declared)
2. You're not using a null terminated string
Best case is that it'll compile with some warnings on a non-standard compiler like VC6, worst case (And likely case) is that your app crashes horribly.
You should do something like this:
if (id[0]=='R' && id[1]=='I' && id[2]=='F' && id[3]=='F')
I.e. compare each byte. Or use memcmp or similar - Although if you're only checking 4 bytes, I'd just use the above way.
1. You're comparing unsigned chars (Which is how a BYTE is declared)
2. You're not using a null terminated string
Best case is that it'll compile with some warnings on a non-standard compiler like VC6, worst case (And likely case) is that your app crashes horribly.
You should do something like this:
if (id[0]=='R' && id[1]=='I' && id[2]=='F' && id[3]=='F')
I.e. compare each byte. Or use memcmp or similar - Although if you're only checking 4 bytes, I'd just use the above way.
This topic is closed to new replies.
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