Lỗi trong thuật toán huffman trong lập trình

như tiêu đề trong lúc khai báo thuận toán nén huffman thì e bị lỗi ở phần cuối bài fix mãi ko biết cách mong bác nào hướng dẫn với ạ.
-Mình bị lỗi C:UsersWWWDesktopNew folder (2)hihi.cpp [Error] ‘input’ was not declared in this scope

#include <stdio.h> 
#include <conio.h>

struct  NODE   { 
 unsigned  char c ; //   k y   t u 
 int 	 freq ; 	 //   s o   l a n   x u a t   h i e n 
 bool 	 used ; 	 //   d a n h   d a u   n o d e   d a   x u   l y   c h u a   
 int 	 nLeft ; 	 //   c h i   s o   n u t   c o n   n a m   b e n   t r a i 
 int 	 nRight ; 	 //   c h i   s o   n u t   c o n   n a m   b e n   p h a i 
  } ; 
  
 struct   MABIT   { 
  char *  bits ; 
  int 	  soBit ; 
 } ; 
 const  int   MAX_NODE = 256 * 9 ; 
 const  int   MAX_BIT_LEN = 10000 ; 
 NODE huffTree [MAX_NODE] ; 
 MABIT	bangMaBit [256] ; 	 
 
 void   KhoiTao ( ){ 
 for   ( int  i = 0 ; i < MAX_NODE;i++) { 
    huffTree[i].c = i ; 
    huffTree [i].freq = 0 ; 
	huffTree[i].used = false;  
 	huffTree[i].nLeft = - 1 ; 
 	huffTree[i].nRight = - 1 ; 
 	 }
 } 
 
 void   ThongKeTanSoXuatHien(char*tenFile){ 	 
 FILE*fi = fopen (tenFile ,"rt") ;  
 unsigned  char c ; 
 while (1) { 	 	 
 fscanf (fi,"%c",&c ) ; 
 if (feof(fi)){ 
 break ; 
 } 
 huffTree[c].freq++;
 } 
 fclose(fi); 
 } 
 
 void  XuatBangThongKe( ){ 
 printf("Bang thong ke tan suat:
") ; 
 for(int i=0;i<256;i++){ 
 if(huffTree[i].freq>0) { 
 printf("%c:%d
",i,huffTree[i].freq);
 		} 
 	} 
 
 } 
 
 void XuatBanThongKe(){
	printf("Bang thong ke tan suat: 
");
	for (int i = 0; i < 256; i++){
	if (huffTree[i].freq > 0){
		printf("%c: %d
",i, huffTree[i].freq);
	}
  }
}
bool Tim2PhanTuMin(int &i, int &j, int nNode) {
	i = -1;
	j = -1;
for (int k = 0; k < nNode; k++)
  if (huffTree[k].used == false && huffTree[k].freq >0){
  	if (i == -1){
  		i = k;
	  }
	  else if (j == -1){
	  	j = k;
	  }
	  else{
	  	if (huffTree[i].freq > huffTree[j].freq){
	  	   if (huffTree[k].freq < huffTree[i].freq){
	  	   	i = k;
			 }
		  }
		else{
			if (huffTree[k].freq < huffTree[j].freq){
				j = k;
			}
		 }
	  }
  }
if (i!= -1 && j!= -1){
	if ((huffTree[i].freq > huffTree[j].freq) || ((huffTree[i].freq > huffTree[j].freq) && (huffTree[i].c > huffTree[j].c))){
		int t = i;
		i = j;
		j = t;
	}
	return true;
}
else {
	return false;
 }
}
 
 int   TaoCayHuffman( ) { 
 
 	 int   nNODE   =   256 ; 
 
 	 int   i , j ; 
 
 	 bool   timthay =  false ; 
 
 	 while   ( true ) 	 { 
       timthay =  Tim2PhanTuMin( i , j , nNODE ) ; 
 
 	   if   (!timthay)  { 
 
 	 	break ; 
        } 

 	 	 huffTree[nNODE].c = (huffTree[i].c < huffTree[j].c)   ?   huffTree[i].c : huffTree [j].c ;   
 
 	 	 huffTree[nNODE].freq = huffTree[i].freq + huffTree[j].freq ; 
 
 	 	 huffTree[nNODE]. nLeft  =   i ; 
 
 	 	 huffTree[nNODE]. nRight =   j ; 
 
 	 	 huffTree[i].used = true ; 
 
 	 	 huffTree[j].used = true ; 
 	 	 
 	 	 huffTree[nNODE].used = false ; 
 
 	 	 nNODE++; 
		   } 
 
 	 return   nNODE -1 ; 
 } 
 
 void   XuatCayHuffman ( int node , int tab )   { 
 
 	 if   ( node == -1 )   { 
 
 	 	 return ; 
 
 	 } 
 
 	 for   ( int i = 0 ; i < tab; i++ )   { 
 
 	 	 printf ("	") ; 
 	 } 
 	 if   (huffTree[node].nLeft == - 1 && huffTree[node].nRight == -1 ) 	 { 
 
 	 	 printf("%c
" , huffTree[node].c)
		   ; 
 } 
 
 	 else 	 { 
 
 	 	 printf("%c..
", huffTree[node].c ) ; 
 
 	 	 XuatCayHuffman(huffTree[node].nLeft, tab + 1 ) ; 
 
 	 	 XuatCayHuffman(huffTree[node].nRight, tab + 1 ) ; 
 	 } 
 } 
 
 void   DuyetCayHuffman (int   node,   char   maBit [ ] , int   nMaBit )   { 
 
 	 if   (node == -1 )   { 
       return ; 
 } 
 
 	 if  (huffTree[node].nLeft == -1 && huffTree[node].nRight == -1 ) {
 
 	 	 bangMaBit [node].soBit =  nMaBit; 
 
 	 	 bangMaBit [node].bits = new  char [nMaBit] ; 
 
 	 	 for   ( int  i = 0 ; i < nMaBit; i++) { 
 
 	 	 	 bangMaBit[node].bits[i]= maBit[i] ; 
 
 	 	 } 
 	 	 return ; 
 	 } 
 
 	 else  {  
 
 	 	maBit[nMaBit] = 0 ; 	 	 
 
 	 	DuyetCayHuffman(huffTree[node].nLeft, maBit , nMaBit + 1) ;  
 
 	 	 maBit [ nMaBit ]  = 1 ; 
 
 	 	 DuyetCayHuffman(huffTree[node].nRight, maBit , nMaBit + 1 ) ; 
 	 } 
 } 
 
 void   PhatSinhMaBit( int  nRoot ) {
  for   ( int i = 0 ; i < 256 ; i++ )   { 
 	bangMaBit[i].soBit = 0 ; 
	bangMaBit[i].bits = NULL ; 
 } ; 
 char maBit[MAX_BIT_LEN/8] ; 
 	int  nMaBit = 0 ; 
	DuyetCayHuffman(nRoot, maBit, nMaBit) ; 
  } 
 
 
 void   XuatBangMaBit ( ) { 
 for (int i = 0 ; i < 256 ; i++ ) 
 if  (bangMaBit[i].soBit > 0 ) { 
 printf("%c: ", i ) ; 
 for (int j = 0; j < bangMaBit[i].soBit;j ++ ) 	 
 printf("%d",  bangMaBit[i].bits[j]); 
 printf("
" ); 
  	 } 
 } 
 
 void   XuatByte ( unsigned char out , int  soBitCoNghia )   { 
 
 	 for  (int i = 7; i > 7 - soBitCoNghia + 1 ; i-- )   { 
 
 	 	 if ( ( out >> i ) & 1 )   {
 
 	 	 	printf ( "1" ) ; 
 
 	 	 } 
 
 	 	 else  { 
 
 	 	 	 printf( " 0 " ) ; 	 	 
 
 	 	 } 
 
 	 } 
 
 	 printf ( " " ) ; 
 
 } 
 
 
 
 void  MaHoa1KyTu ( unsigned  char c ,   unsigned char & out ,   unsigned  char & viTriBit)   {  
 
 	 for (int i =  0 ; i <  bangMaBit[c].soBit; i++ )   { 
 
 	 	 if  ( bangMaBit[c].bits[i] == 1 )   { 
 
 	 	 	 out = out | ( 1 << viTriBit ) ; 
 
 	 	 } 
 
 	 	 if  (viTriBit == 0 )   {   
 	 	 	 viTriBit = 7 ; 
 	 	 	 XuatByte( out, 8 ) ; 
 	 	 	 out = 0 ; 
 
 	 	 } 
 
 	 	 else   { 
 
 	 	 	 viTriBit -- ; 
 
 	 	 } 
 
 	 } 
 
 } 
 
 
 
 void   NenHuffman( char*inputFile )   { 
 
 //buoc 1: thong ke tuan so xuat hien
 	 KhoiTao ( ) ; 
 	 ThongKeTanSoXuatHien (inputFile ) ; 	 
  	 XuatBangThongKe ( ) ; 
 //buoc 2: tao cay huffman
 	 int   nRoot = TaoCayHuffman ( ) ; 
  	 XuatCayHuffman(nRoot, 0 ) ;  
 //buoc 3 : phat sinh mabit  
 	 PhatSinhMaBit( nRoot ) ; 	 
 	 XuatBangMaBit ( ) ; 
 //buoc 4: thay ki tu bang mabit 
 
 	 unsigned char out =  0 ; 	 	 	 	 // ky tu xuat ra  
 
 	 unsigned char soBitCoNghia = 0 ; 	 	 // lu lai sobit co nghia
 	 unsigned char  c ; 
 
 	 unsigned char  viTriBit = 7 ; 	 	 	 
 
 	 FILE*fi = fopen(inputFile," rt " ) ; 
 
 	 while  ( true )   { 	 
 
 	 	 fscanf ( fi , " %c " , & c ) ; 
 
 	 	 if (feof ( fi ) )   { 
 
 	 	 	 break ; 
 	 	 } 
 	 	 MaHoa1KyTu( c , out , viTriBit ) ; 
 }  
 	 soBitCoNghia = 7 - viTriBit ; 
 	 
 	 if  ( soBitCoNghia == 0 )   { 	 
	  	 	 	 
 	  soBitCoNghia = 8 ; 
 	 } 
 	 else   { 
        
		XuatByte ( out , soBitCoNghia ) ; 
 	} 
 	 
	  fclose (fi) ;  
 } 
 
 int   main (){ 
 NenHuffman (input.txt);
 }