How to read array saved in binary mode to text file in C

Question

I have an array of string saved like so:

char clientdata[5][128];
char buffer[256];
... input values into array ...
FILE *f = fopen("client.txt", "w+b");
fwrite(clientdata, sizeof(char), sizeof(clientdata), f);
... read the array from file ...
fclose(f);

Now I want to read the array from the file in that above code. I tried:

fread(clientdata, sizeof(char), sizeof(clientdata), f);

Then I tried to use sprintf on clientdata:

 sprintf(buffer,"%s",clientdata[1]);

this gave me the error :

request for member in clientdata not a structure or union

What did I do wrong?

Start by checking the return values of *every* file api you're calling (after you fix your compile-time error, of course). — WhozCraig, Sep 03 '13 at 18:53
The converse of the problem in [How to write an array to file in C?](http://stackoverflow.com/questions/18597685/how-to-write-an-array-to-file-in-c/) — Jonathan Leffler, Sep 03 '13 at 22:00

ryyker · Answer 1 · 2013-09-03T20:23:41.023

As others have noted, you have not provided anything to explain where

request for member in something not a structure or union

would have come from, in your code for example, we do not see buffer defined anywhere... In any case:

Brute force method: (compiles, builds and runs as is in ANSI C)

#include <ansi_c.h>
#define newBinaryFile "C:\\tempExtract\\newbinaryfile.bin"
int main(void)
{
    FILE *fp;
    int i;
    char clientDataNew[5][128] = {"","","","",""};
    char clientdata[5][128] = {  "This string is 128 bytes longggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggg1\n",
                                 "This string is 128 bytes longggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggg2\n",
                                 "This string is 128 bytes longggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggg3\n",
                                 "This string is 128 bytes longggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggg4\n",
                                 "This string is 128 bytes longggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggg5\n"};

    fp = fopen (newBinaryFile, "wb");

    fwrite(clientdata, sizeof(char), sizeof(clientdata), fp);
//  for(i=0;i<5;i++)
//  {
//      fputs(clientdata[i], fp);
//  }
    fclose (fp);

    fopen(newBinaryFile, "rb");

    fread(clientDataNew, sizeof(char),sizeof(clientdata),fp);

    for(i=0;i<5;i++)
    {
        (fgets (clientDataNew[i], 128, fp));
    }
    fclose(fp);
    for(i=0;i<5;i++)
    {
        printf("%s", clientDataNew[i]); 
    }
    getchar();
    return 0;   
}

is it not possible to do w+b instead of having to reopen the file? — mugetsu, Sep 04 '13 at 18:31
Yes - look at ***[fopen(...,"wb")](http://pubs.opengroup.org/onlinepubs/009696799/functions/fopen.html)***. Also ***[fseek](http://pubs.opengroup.org/onlinepubs/009696799/functions/fseek.html)*** may come in handy for resetting the pointer to the stream — ryyker, Sep 09 '13 at 22:11

How to read array saved in binary mode to text file in C

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