Problems reading a binary file with fread function

Question

What I want to do is to read the contents of a '.d' binary file and store them in an array. So I wrote the following codes:

void viewFile()
{
   unsigned char inFileData[SIZE];
   char fileName[SIZE];
   int numRead;

   FILE *inBinFile;


    printf("Enter the file name:");
    scanf("%s", fileName);

    inBinFile = fopen( fileName, "rb");
        if(( inBinFile = fopen(fileName, "rb")) == NULL )
        {
           fprintf( stderr, "Error opening %s\n", fileName );
           clearStdin();/*a function to clear stdin*/
           mainMenu();/*a function to prompt user input*/
        }
    numRead = fread( inFileData, sizeof(unsigned char), SIZE, inBinFile );
    inFileData[SIZE] = '\0';

    printf("U coded data:\n%s\n", inFileData);
    printf("%d\n", numRead);

    fclose(inBinFile);
   return;
}

the output is an unreadable pile of junk. Which part did I do wrong? I don't get it.

also, I wrote my clearStdin function as below:

void clearStdin(void)
{
    scanf("%*[^\n]");
    scanf("%*1[\n]");
   return;
}

compiler reported no errors, but somehow the function call doesn't seem to work exactly the way I wanted. It did clear stdin, but there are always errors closely following wherever this function is called, eg., the mainmenu function to prompt user input.

Please help!! thanks in advance.

Unless the contents of a binary file is a readable set of ASCII characters, sending the contents to stdout using a %s printf() format should generally result in an unreadable pile of junk. What is actually in the file? — Michael Burr
– Michael Burr, Commented Aug 22, 2012 at 6:38
What else would you expect - you said yourself the file was binary and so why would it yield readable output? — mathematician1975
– mathematician1975, Commented Aug 22, 2012 at 6:38
Micheal, the actual content is just 0 1 2 3 4 5 6 7 8 9. That's where I got confused.. thanks! — David Chu
– David Chu, Commented Aug 22, 2012 at 6:47
mathematician1975 the design specification said that the content is 0 1 2 3 4 5 6 7 8 9, so i want to print it... sorry for not making it clear enough and thank you! — David Chu
– David Chu, Commented Aug 22, 2012 at 6:48

Community · Accepted Answer · 2017-05-23 11:56:15Z

2

"the output is an unreadable pile of junk" - yes, it will be. It's a binary file, it's not meant to be readable as text.

If you want to see binary information in a readable form, think about doing a hex dump of it.

See here for a way to do this.

edited May 23, 2017 at 11:56

CommunityBot

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answered Aug 22, 2012 at 6:37

paxdiablo

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