Thread: need a little help reading binary data in from a file

ok this is gonna sound extremely dumb, but i have to ask. I have a binary data file and i want to open it to read it into my program using the fopen() function. Now its been a while since i used C, but i as i remember it the way to do this would be to put the following statement in to my code

Code:

 
fp=fopen("c:\test.bin", rb);

where c:\test.bin is the address of the file i want to open. Yet when i compile my code i get this errors

error C2065 : 'wb' : undeclared identifier

error C4047: 'function' : 'const char*' differs in levels of direction from 'int'

Can anybody give me any ideas what the problem is?

Thanks in advance

Andy

yeah, in my actual code i do check to make sure fopen worked thanks for the pointer though. Its been a while since i used C and im just testing ideas at the moment to get back into it, but as a second questions. If i input the following code

Code:

	char x[10]="ABCDEFGHIJ";
	FILE *fp;
	if((fp=fopen("c:\\test.bin", "wb"))==NULL)
	{
                       printf("Couldnot open file");
                       exit(1);
                }
	fwrite(x, sizeof(x[0]), sizeof(x)/sizeof(x[0]), fp);

	fcloseall();
	return(0);

should the file test.bin contain the binary version of ABCDEFGHIJ or should it show ABCDEFGHIJ if opened in notepad?

Originally Posted by andydavenport

yeah, in my actual code i do check to make sure fopen worked thanks for the pointer though. Its been a while since i used C and im just testing ideas at the moment to get back into it, but as a second questions. If i input the following code

Code:

	char x[10]="ABCDEFGHIJ";
	FILE *fp;
	if((fp=fopen("c:\\test.bin", "wb"))==NULL)
	{
                       printf("Couldnot open file");
                       exit(1);
                }
	fwrite(x, sizeof(x[0]), sizeof(x)/sizeof(x[0]), fp);

	fcloseall();
	return(0);

should the file test.bin contain the binary version of ABCDEFGHIJ or should it show ABCDEFGHIJ if opened in notepad?

I don't know about you but I usually use types in sizeof

Code:

 
                int len = 10;
	char x[len]="ABCDEFGHIJ";
	FILE *fp;
	if((fp=fopen("c:\\test.bin", "wb"))==NULL)
	{
                       printf("Couldnot open file");
                       exit(1);
                }
	fwrite(x, sizeof(char), len, fp);

	fcloseall();
	return(0);

and yes it will show ABCDEFGHIJ in notepad because you are printing ascii characters.

cheers

i tell you blowing the cobebs outta the old brain is getting harder to do

Using types in sizeof is not required it's just something I prefer to do because it makes more sense when I read it.

ok, how do i get it to make the out put file into binary data, rather that ascii characters?