C Concatenate string in while loop -

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• c concatenate string in while loop 2 answers

i cant seem use following function concatenate string in while loop. idea im doing wrong?

void do_file(file *in, file *out, options *options) {     char ch;     int loop = 0;     int sz1,sz2,sz3;      int seeker = offsetof(struct mystruct, contents.datas);      //find total length of file     fseek(in, 0l, seek_end);     sz1 = ftell(in);      //find length struct beginning , minus total length     fseek(in, seeker, seek_set);     sz2 = sz1 - ftell(in);      sz3 = (sz2 + 1) * 2;//allocate enough size 2x array length     char buffer[sz3];//set size of buffer copied     char msg[sz3];//set size of msg      buffer[0] = '\0';      while (loop < sz2)     {         if (loop == sz2)         {             break;         }          fread(&ch, 1, 1, in);         //sprintf(msg, "%02x", (ch & 0x00ff));         strcat(buffer, msg);          ++loop;     }     printf("%s\n", buffer); } 

your strcat appends char msg[sz3]; never filled.

edit simplest fix add

msg[1] = '\0'; 

after

char msg[sz3];//set size of msg 

and replace

fread(&ch, 1, 1, in); 

with

fread(&msg[0], 1, 1, in);