How to replace fread() from file, with command line argument?

Question

I have the following code:

uint8_t in[BLOCK256], out[32];
bytesread = fread( in, 1, BLOCK256, fp );

then the in variable is passed to another function.

I was trying to substitute the reading from file functionality with inserting a string as an argument to the program using strcpy(in,argv[1]) .

The result I am getting though its different in those two cases. I am not sure what the problem is.

int main( int argc, char **argv )
{
    #define BLOCK256 64
    FILE *fp;
    int i, j, bytesread;
    uint8_t in[BLOCK256], out[32];
    state256 S;
    blake256_test();

    for( i = 1; i < argc; ++i )
    {
        fp = fopen( *( argv + i ), "r" );
        if ( fp == NULL )
        {
            printf( "Error: unable to open %s\n", *( argv + i ) );
            return 1;
        }

        blake256_init( &S );

        while( 1 )
        {
            bytesread = fread( in, 1, BLOCK256, fp );
            if ( bytesread )
               blake256_update( &S, in, bytesread );
            else
               break;
        }

        blake256_final( &S, out );

        for( j = 0; j < 32; ++j )
           printf( "%02x", out[j] );

        fclose( fp );
    }
    return 0;
}

Instead of reading the contents of a file I want to pass a string as a command line argument.

Answer 1

int main(argc, argv[]){
     state256 S;
     blake_test();
     unsigned char digest[32];
     for (i=1; i < argc; i++){
          blake256_init(&S);
          blake256_update(&S,argv[i], strlen(argv[i]));
          blake256_final(&S, digest);
          print_digest(digest); /* your print loop as function, with extra newline */
     }
     return 0;
}

will do the trick (hash every commandline argument string). Write the print function and add string.h headerfiles etc. BTW you are not reading from stdin in either case.