I have added data to the file using one char variable and 1 integer if I want to check the data with the string variable i am not able to check that

* I am working on my attendance mini project .I want to check the string variable is entered in present in my file or not .There is problem in my check_data() function .Kindly help me out *

 #include<fstream>
#include<iostream>
using namespace std;
class attend
{
int idn;
char ar[10];
public:
   void getdata()
   {
    cout<<"ENTER THE ROLL NUMBER \n";
    cin>>idn;
    fstream fout("AT1.txt",ios::app);
    fout<<"\n"<<idn;
    cout<<"ENTER THE NAME "<<endl;
    cin>>ar;
    fout<<"\t"<<ar;
    fout.close();
  }
   void check_data()
   {
    char i,chk[10];
   cout<<"ENTER THE NAME TO CHECK "<<"\n";
   cin>>chk;
   fstream fin("AT1.txt",ios::in);
              while(!fin.eof())
            {
                fin>>ar;
                cout<<"\n"<<ar;
                for(i=0;i<10;i++)
                {
                if(chk[i]==ar[i])
                {
                    cout<<"DATA FOUND ";
                }
                }
            }   
   }    
};
int main()
{
    attend obj;
    obj.getdata();
    obj.check_data();
}