Language: C++

#include<iostream>
#include<algorithm>
#include<string>
using namespace std;
 
long long dec(string s)
{
  long long h=1,d=0;
  for(int i=s.length()-1;i>=0;i--){
    if(s[i]=='a')d+=10*h;
    else if(s[i]=='b')d+=11*h;
    else if(s[i]=='c')d+=12*h;
    else if(s[i]=='d')d+=13*h;
    else if(s[i]=='e')d+=14*h;
    else if(s[i]=='f')d+=15*h;
    else d+=(s[i]-'0')*h;
    h*=16;
  }
  return d;
}
 
string hex(long long dec)
{
  string h="";
  for(int i=0;i<8;i++){
    int b=dec%16;
    dec=dec/16;
    if(b==10)h+='a';
    else if(b==11)h+='b';
    else if(b==12)h+='c';
    else if(b==13)h+='d';
    else if(b==14)h+='e';
    else if(b==15)h+='f';
    else h+=('0'+b);
    if(dec==0)break;
  }
  reverse(h.begin(),h.end());
  return h; 
}
 
int main()
{
  long long N[9],k,sum,d;
  string a;
  int S,x,y;
 
  cin>>S;
  
  for(int n=0;n<S;n++){
    for(int i=0;i<9;i++){
      cin>>a;
      N[i]=dec(a);
    }
    k=0;d=1;
    for(int i=0;i<32;i++){
      sum=0;
      for(int j=0;j<8;j++){
    sum+=N[j];
    sum%=4294967296;
      }
      x=(sum/d)%2;
      y=(N[8]/d)%2;
      if(x!=y){
        k+=d;
    for(int j=0;j<8;j++)N[j]=N[j]^d;
      }
      d*=2;
    }
    cout<<hex(k)<<endl;
 
  }
  return 0;
}


Compiler output:
a.cc:5:1: error: extended character   is not valid in an identifier
    5 |  
      | ^
a.cc:8:1: error: extended character   is not valid in an identifier
    8 |   long long h=1,d=0;
      | ^
a.cc:8:1: error: extended character   is not valid in an identifier
a.cc:9:1: error: extended character   is not valid in an identifier
    9 |   for(int i=s.length()-1;i>=0;i--){
      | ^
a.cc:9:1: error: extended character   is not valid in an identifier
a.cc:10:1: error: extended character   is not valid in an identifier
   10 |     if(s[i]=='a')d+=10*h;
      | ^
a.cc:10:1: error: extended character   is not valid in an identifier
a.cc:10:1: error: extended character   is not valid in an identifier
a.cc:10:1: error: extended character   is not valid in an identifier
a.cc:11:1: error: extended character   is not valid in an identifier
   11 |     else if(s[i]=='b')d+=11*h;
      | ^
a.cc:11:1: error: extended character   is not valid in an identifier
a.cc:11:1: error: extended character   is not valid in an identifier
a.cc:11:1: error: extended character   is not valid in an identifier
a.cc:12:1: error: extended character   is not valid in an identifier
   12 |     else if(s[i]=='c')d+=12*h;
      | ^
a.cc:12:1: error: extended character   is not valid in an identifier
a.cc:12:1: error: extended character   is not valid in an identifier
a.cc:12:1: error: extended character   is not valid in an identifier
a.cc:13:1: error: extended character   is not valid in an identifier
   13 |     else if(s[i]=='d')d+=13*h;
      | ^
a.cc:13:1: error: extended character   is not valid in an identifier
a.cc:13:1: error: extended character   is not valid in an identifier
a.cc:13:1: error: extended character   is not valid in an identifier
a.cc:14:1: error: extended character   is not valid in an identifier
   14 |     else if(s[i]=='e')d+=14*h;
      | ^
a.cc:14:1: error: extended character   is not valid in an identifier
a.cc:14:1: error: extended character   is not valid in an identifier
a.cc:14:1: error: extended character   is not valid in an identifier
a.cc:15:1: error: extended character   is not valid in an identifier
   15 |     else if(s[i]=='f')d+=15*h;
      | ^
a.cc:15:1: error: extended character   is not valid in an identifier
a.cc:15:1: error: extended character   is not valid in an identifier
a.cc:15:1: error: extended character   is not valid in an identifier
a.cc:16:1: error: extended character   is not valid in an identifier
   16 |     else d+=(s[i]-'0')*h;
      | ^
a.cc:16:1: error: extended character   is not valid in an identifier
a.cc:16:1: error: extended character   is not valid in an identifier
a.cc:16:1: error: extended character   is not valid in an identifier
a.cc:17:1: error: extended character   is not valid in an identifier
   17 |     h*=16;
      | ^
a.cc:17:1: error: extended character   is not valid in an identifier
a.cc:17:1: error: extended character   is not valid in an identifier
a.cc:17:1: error: extended character   is not valid in an identifier
a.cc:18:1: error: extended character   is not valid in an identifier
   18 |   }
      | ^
a.cc:18:1: error: extended character   is not valid in an identifier
a.cc:19:1: error: extended character   is not valid in an identifier
   19 |   return d;
      | ^
a.cc:19:1: error: extended character   is not valid in an identifier
a.cc:21:1: error: extended character   is not valid in an identifier
   21 |  
      | ^
a.cc:24:1: error: extended character   is not valid in an identifier
   24 |   string h="";
      | ^
a.cc:24:1: error: extended character   is not valid in an identifier
a.cc:25:1: error: extended character   is not valid in an identifier
   25 |   for(int i=0;i<8;i++){
      | ^
a.cc:25:1: error: extended character   is not valid in an identifier
a.cc:26:1: error: extended character   is not valid in an identifier
   26 |     int b=dec%16;
      | ^
a.cc:26:1: error: extended character   is not valid in an identifier
a.cc:26:1: error: extended character   is not valid in an identifier
a.cc:26:1: error: extended character   is not valid in an identifier
a.cc:27:1: error: extended character   is not valid in an identifier
   27 |     dec=dec/16;
      | ^
a.cc:27:1: error: extended character   is not valid in an identifier
a.cc:27:1: error: extended character   is not valid in an identifier
a.cc:27:1: error: extended character   is not valid in an identifier
a.cc:28:1: error: extended character   is not valid in an identifier
   28 |     if(b==10)h+='a';
      | ^
a.cc:28:1: error: extended character   is not valid in an identifier
a.cc:28:1: error: extended character   is not valid in an identifier
a.cc:28:1: error: extended character   is not valid in an identifier
a.cc:29:1: error: extended character   is not valid in an identifier
   29 |     else if(b==11)h+='b';
      | ^
a.cc:29:1: error: extended character   is not valid in an identifier
a.cc:29:1: error: extended character   is not valid in an identifier
a.cc:29:1: error: extended character   is not valid in an identifier
a.cc:30:1: error: extended character   is not valid in an identifier
   30 |     else if(b==12)h+='c';
      | ^
a.cc:30:1: error: extended character   is not valid in an identifier
a.cc:30:1: error: extended character   is not valid in an identifier
a.cc:30:1: error: extended character   is not valid in an identifier
a.cc:31:1: error: extended character   is not valid in an identifier
   31 |     else if(b==13)h+='d';
      | ^
a.cc:31:1: error: extended character   is not valid in an identifier
a.cc:31:1: error: extended character   is not valid in an identifier
a.cc:31:1: error: extended character   is not valid in an identifier
a.cc:32:1: error: extended character   is not valid in an identifier
   32 |     else if(b==14)h+='e';
      | ^
a.cc:32:1: error: extended character   is not valid in an identifier
a.cc:32:1: error: extended character   is not valid in an identifier
a.cc:32:1: error: extended character   is not valid in an identifier
a.cc:33:1: error: extended character   is not valid in an identifier
   33 |     else if(b==15)h+='f';
      | ^
a.cc:33:1: error: extended character   is not valid in an identifier
a.cc:33:1: error: extended character   is not valid in an identifier
a.cc:33:1: error: extended character   is not valid in an identifier
a.cc:34:1: error: extended character   is not valid in an identifier
   34 |     else h+=('0'+b);
      | ^
a.cc:34:1: error: extended character   is not valid in an identifier
a.cc:34:1: error: extended character   is not valid in an identifier
a.cc:34:1: error: extended character   is not valid in an identifier
a.cc:35:1: error: extended character   is not valid in an identifier
   35 |     if(dec==0)break;
      | ^
a.cc:35:1: error: extended character   is not valid in an identifier
a.cc:35:1: error: extended character   is not valid in an identifier
a.cc:35:1: error: extended character   is not valid in an identifier
a.cc:36:1: error: extended character   is not valid in an identifier
   36 |   }
      | ^
a.cc:36:1: error: extended character   is not valid in an identifier
a.cc:37:1: error: extended character   is not valid in an identifier
   37 |   reverse(h.begin(),h.end());
      | ^
a.cc:37:1: error: extended character   is not valid in an identifier
a.cc:38:1: error: extended character   is not valid in an identifier
   38 |   return h;
      | ^
a.cc:38:1: error: extended character   is not valid in an identifier
a.cc:40:1: error: extended character   is not valid in an identifier
   40 |  
      | ^
a.cc:43:1: error: extended character   is not valid in an identifier
   43 |   long long N[9],k,sum,d;
      | ^
a.cc:43:1: error: extended character   is not valid in an identifier
a.cc:44:1: error: extended character   is not valid in an identifier
   44 |   string a;
      | ^
a.cc:44:1: error: extended character   is not valid in an identifier
a.cc:45:1: error: extended character   is not valid in an identifier
   45 |   int S,x,y;
      | ^
a.cc:45:1: error: extended character   is not valid in an identifier
a.cc:46:1: error: extended character   is not valid in an identifier
   46 |  
      | ^
a.cc:47:1: error: extended character   is not valid in an identifier
   47 |   cin>>S;
      | ^
a.cc:47:1: error: extended character   is not valid in an identifier
a.cc:48:1: error: extended character   is not valid in an identifier
   48 |   
      | ^
a.cc:48:1: error: extended character   is not valid in an identifier
a.cc:49:1: error: extended character   is not valid in an identifier
   49 |   for(int n=0;n<S;n++){
      | ^
a.cc:49:1: error: extended character   is not valid in an identifier
a.cc:50:1: error: extended character   is not valid in an identifier
   50 |     for(int i=0;i<9;i++){
      | ^
a.cc:50:1: error: extended character   is not valid in an identifier
a.cc:50:1: error: extended character   is not valid in an identifier
a.cc:50:1: error: extended character   is not valid in an identifier
a.cc:51:1: error: extended character   is not valid in an identifier
   51 |       cin>>a;
      | ^
a.cc:51:1: error: extended character   is not valid in an identifier
a.cc:51:1: error: extended character   is not valid in an identifier
a.cc:51:1: error: extended character   is not valid in an identifier
a.cc:51:1: error: extended character   is not valid in an identifier
a.cc:51:1: error: extended character   is not valid in an identifier
a.cc:52:1: error: extended character   is not valid in an identifier
   52 |       N[i]=dec(a);
      | ^
a.cc:52:1: error: extended character   is not valid in an identifier
a.cc:52:1: error: extended character   is not valid in an identifier
a.cc:52:1: error: extended character   is not valid in an identifier
a.cc:52:1: error: extended character   is not valid in an identifier
a.cc:52:1: error: extended character   is not valid in an identifier
a.cc:53:1: error: extended character   is not valid in an identifier
   53 |     }
      | ^
a.cc:53: