UTF-8の全角を出力するプログラム

/*ひな型Hello*/
#include <stdio.h>

main(){
   int a,b,c;
   FILE *fp;

   fp=fopen("723a.txt","wb");
   if(fp==NULL){
      printf("fail\n");
      return;
   }

   for(a=0xe1;a<=0xec;a++){
      for(b=0x80;b<=0xbf;b++){
         for(c=0x80;c<=0xbf;c++){
            printf("%c",a);
            printf("%c",b);
            printf("%c",c);
            fprintf(fp,"%c",a);
            fprintf(fp,"%c",b);
            fprintf(fp,"%c",c);
            if((c%16)==15){
               printf("\n");
               fprintf(fp,"\n");
            }
         }
     }
  }
  fclose(fp);
}