MFC Uniocd编码转GB2312编码问题：报错

#include<iostream>  
using namespace std;  
  
char dec2hexChar(short int n) {  
 if ( 0 <= n && n <= 9 ) {  
  return char( short('0') + n );  
 } else if ( 10 <= n && n <= 15 ) {  
  return char( short('A') + n - 10 );  
 } else {  
  return char(0);  
 }  
}  
  
short int hexChar2dec(char c) {  
 if ( '0'<=c && c<='9' ) {  
  return short(c-'0');  
 } else if ( 'a'<=c && c<='f' ) {  
  return ( short(c-'a') + 10 );  
 } else if ( 'A'<=c && c<='F' ) {  
  return ( short(c-'A') + 10 );  
 } else {  
  return -1;  
 }  
}  
  
string escapeURL(const string &URL)  
{  
 string result = "";  
 for ( unsigned int i=0; i<URL.size(); i++ ) {  
  char c = URL[i];  
  if (  
   ( '0'<=c && c<='9' ) ||  
   ( 'a'<=c && c<='z' ) ||  
   ( 'A'<=c && c<='Z' ) ||  
   c=='/' || c=='.'  
   ) {  
   result += c;  
  } else {  
   int j = (short int)c;  
   if ( j < 0 ) {  
    j += 256;  
   }  
   int i1, i0;  
   i1 = j / 16;  
   i0 = j - i1*16;  
   result += '%';  
   result += dec2hexChar(i1);  
   result += dec2hexChar(i0);  
  }  
 }  
 return result;  
}  
  
string deescapeURL(const string &URL) {  
 string result = "";  
 for ( unsigned int i=0; i<URL.size(); i++ ) {  
  char c = URL[i];  
  if ( c != '%' ) {  
   result += c;  
  } else {  
   char c1 = URL[++i];  
   char c0 = URL[++i];  
   int num = 0;  
   num += hexChar2dec(c1) * 16 + hexChar2dec(c0);  
   result += char(num);  
  }  
 }  
 return result;  
}  
  
int main()  
{  
    string str = "你好";  
    cout<<str<<endl;
    string temp = escapeURL(str);   
    cout<<temp<<endl;
    cout<<deescapeURL(temp)<<endl;   
    return 0;  
}