[Resolution] I have a question about file input/output. An unknown cause error appears.

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <string.h>
#include <dirent.h>
#define MAXCHAR 256


typedef enum {false, true} bool; 

int main(int argc, char ** argv){
  bool is_n=false;
  bool is_o=false;
  bool is_s=false;
    int param_opt;
    int srcfd, dstfd;
    int i, j;
    int filesize = 512;
    int filecount;
    int invalid = 0;
    char buf[3];
    char * srcname;
    char * dstname;
    char * directory="./";
    char * temp;
    char * data;
    char name[MAXCHAR+1];
    ssize_t nread;
    struct stat srcstat;


    if(argc > 1000){
        printf("too many predicates.\n");
        exit(0);
    }
    if(argc < 2){
        printf("need predicate.\n");
        exit(0);
    }

while( -1 !=( param_opt = getopt( argc, argv, "o:n:x:d:")))
   {
      switch( param_opt)
      {
      case  'n'   :  is_n  = true;
                 temp   = optarg; 
                 break;
      case  's'   :  is_s  = true;
                 filesize=atoi(optarg);
                 break;
      case  'o'   :  is_o  = true;
                 srcname = optarg;
                 dstname = optarg;
                 break;
      case  'd'   :  strcat(directory, optarg);
                 break;
      case  '?'   :  printf( "ERROR: %cn", optopt); 
                 break;

      }
   }


   if(is_o==false){
     exit(1);
     }

   if(is_n==true){
     strcpy(dstname,temp);
     }




    printf("file size            = %dkb\n", filesize);
    printf("source filename      = %s\n", srcname);
    printf("destination filename = %s\n", dstname);
    printf("directory            = %s\n", directory);


    if((srcfd = open(srcname, O_RDONLY)) < 0){
        printf("file open error!\n");
        exit(1);
    }


    if(fstat(srcfd, &srcstat) == -1){
        printf("fstat error!\n");
        close(srcfd);
        exit(1);
    }

//  //  printf("file size : %d", srcstat.st_size);



    if(srcstat.st_size < filesize*1024){
        printf("file size is small than %d Kb\n", filesize);
//      //      close(srcfd);
//      //      exit(1);
    }


    filecount = (srcstat.st_size / (filesize*1024)) + 1;
    printf("%ld / %d \n", srcstat.st_size, filesize);


    if(filecount > 999){
        printf("too many file create.(more then 999)\n");
        printf("input size more than %d\n", filesize);
        close(srcfd);
        exit(1);
    }

    if(opendir(directory) == NULL){
        mkdir(directory, 0777);
    }

    data = (char *)malloc(sizeof(char)*filesize+1);
    strcpy(data,"");
    for(i = 0 ; i < filecount ; i++){


        sprintf(name,"%s%s%d",directory,dstname,i);

        printf("file name : %s\n",name);

        if(dstfd = open(name, O_WRONLY | O_CREAT | O_TRUNC)<0){//, srcstat.st_mode
        printf("OPEN_ERROR\n");
        }
        else{

            if((nread = read(srcfd, data, filesize)) < 0){
                printf("read_ERROR\n");
                break;
                }
            else{


            write(dstfd, data, nread);

            printf("%s\n", name);
            printf("...OK\n");
            }




        close(dstfd);
        }

    }
free(data);
    close(nread);
    close(srcfd);
    return 0;
}

        if(dstfd = open(name, O_WRONLY | O_CREAT | O_TRUNC)<0){//, srcstat.st_mode
        printf("OPEN_ERROR\n");
        }
        else{

            if((nread = read(srcfd, data, filesize)) < 0){
                printf("read_ERROR\n");
                break;
                }
            else{


            write(dstfd, data, nread);

            printf("%s\n", name);
            printf("...OK\n");
            }




        close(dstfd);
        }