C: WAV file not being opened in "rb" - c

Question

I'm having a difficult time trying to open a WAV file for reading. When I compile and run my code, I do not get any errors. I am adding the code that I am messing with (assuming necessary libraries have been called). The program is supposed to display the contents of the WAV file and although I enter a valid filename and extension, the statement "Invalid Filename. Try Again." is still being printed to the screen. The other method I attempted was enter the directory of the file instead of just the name, and when I do that, my program ends and nothing is displayed. Any guidance would be helpful and thank you in advance!
main(){
FILE *fin;
printf("\nEnter filename of WAV file: \n");
char filename[256];
scanf("%s",&filename);
fin = fopen(filename,"rb"); // opens in rb
if(!fin) // if file doesn't exist
{
printf("Invalid filename. Try again.\n");
}
else // if fin opens succesfully
{
printf("\nFile opened succesfully\n");
char *header;
header = (char *)malloc(44);
if(header == NULL)
{
printf("Error in allocating memory.");
return 0;
}
fread(header,1,44,fin);
char *chunkid;
unsigned int *chunksize;
char *format;
char *subchunk1id;
unsigned int *subchunk1size;
unsigned short int *audioformat;
unsigned short int *numchannels;
unsigned int *samplerate;
unsigned int *byterate;
unsigned short int *blockalign;
unsigned short int *bitspersample;
char *subchunk2id;
unsigned int *subchunk2size;
unsigned int *data;
chunkid = header;
chunksize = (unsigned int *)(header + 4);
format = header + 8;
subchunk1id = header + 12;
subchunk1size = (unsigned int *)(header + 16);
audioformat = (unsigned short int *)(header + 18);
numchannels = (unsigned short int*)(header + 20);
samplerate = (unsigned int*)(header + 24);
byterate = (unsigned int*)(header + 28);
blockalign = (unsigned short int*)(header + 30);
bitspersample = (unsigned short int*)(header + 32);
subchunk2id = header + 36;
subchunk2size = (unsigned int*)(header + 40);
data = (unsigned int*)(header + 44);
printf("\n%c%c%c%c",*(header),*(header+1),*(header+2),*(header+3));
printf("\n%d",*chunksize);
printf("\n%c%c%c%c",*(header + 8),*(header + 9), *(header + 10), *(header + 11));
printf("\n%c%c%c%c",*(header + 12),*(header + 13), *(header + 14), *(header + 15));
printf("\n%d",*subchunk1size);
printf("\n%d",*audioformat);
printf("\n%d",*numchannels);
printf("\n%d",*samplerate);
printf("\n%d",*byterate);
printf("\n%d",*blockalign);
printf("\n%d",*bitspersample);
printf("\n%c%c%c%c",*(header + 36),*(header + 37),*(header + 38), *(header + 39));
printf("\n%d",*subchunk2size);
printf("\n%d",*data);
fclose(fin);
} // end of else
} // end of main

Answer 1

Try using
if(!fin)
{
perror("Error:");
}
it will print the right error message for you to easily diagnose why your file couldn't be opened. May be your program cannot find the file specified by you or you might not have permissions to open it. Here's a list of errors you may encounter while opening a file.
The other possible problem that I could see is that you are using scanf to read from stdin into your char array. What if the path specified by you contains white-spaces? Every word followed by a White-space will be considered like a different string. And you'll get only the first longest possible word that doesn't contain white-space into it. So, your program isn't reading the entire path. You can try
scanf("%[^\n]", filename) which will read until a '\n' is encountered. Beware! This exposes you to buffer overflow possibilities, that if you pass a valid string set to the program which is of length greater than 256, you'll be writing beyond the boundaries of your char array and which isn't good. So try scanf("%255[^\n]", filename) or try using fgets() doc SO which provides buffer overflow protection.

Answer 2

Using warnings while compiling the code would have revealed your mistake.
Proposal for improvement, describe the header as a struct like:
typedef struct
{
char riff_tag[4];
int32_t riff_length;
char wave_tag[4];
char fmt_tag[4];
int32_t fmt_length;
int16_t audio_format;
int16_t num_channels;
int32_t sample_rate;
int32_t byte_rate;
int16_t block_align;
int16_t bits_per_sample;
char data_tag[4];
int32_t data_length;
}waveFileHeader, *waveFileHeaderptr ;
and read it like:
waveFileHeaderptr header =malloc ( sizeof (waveFileHeader));
fread (header , sizeof (waveFileHeader), 1 , fin);
will make the following code and handeling less messy