finding_identifiers_of_equations

/* Author : H. M. Tarek Ullah
   Date : 02.03.15
   About : this program identifies identifiers of any equation
*/


#include<bits/stdc++.h>
using namespace std ;

bool isoperator(string s)
{
       for(int i=0 ;i<s.length();i++)
       {
           if(s[i]=='+' || s[i]=='=' || s[i]=='-' || s[i]=='/')
            return true ;
           else if(s[i] >= '0' && s[i]<='9')
               return true ;
           else
            return false ;
       }
}

int main()
{


 string eqn ;
 getline(cin,eqn);
 string r1 ;
 stringstream os(eqn) ;
 vector<string> vec  ;
  while(os>> r1 || !os.eof()){

    vec.push_back(r1);

  }
  vector<string>::const_iterator it1= vec.begin() ;
  vector<string>::const_iterator it2=vec.end() ;


  for(vector<string>::const_iterator it=it1;it!=it2;it++)
  {

       string s = *it ;
       if(isoperator(s)==false)
        cout << *it << endl;
  }

    return 0 ;
}