find and replace string with inheritance in c++

#include<iostream>
#include<conio.h>
#include<string>
using namespace std;
class String
{
      protected:
      string str;
 char Rplce[100];
 string Search;

      int location;
      public:
      void SetStr(string st)
      {
      str=st;
      }
      string getstr()
      {
      return str;
      }
};
class Find_Locaton:public String
{
      public:
      void SetSrc(string st)
      {
     
      Search=st;
      }
     
      int Find_loca()
      {
          location=str.find(Search);
          if(location!=string::npos)
          {
                                   
          return location;
          }
         
          else
          {
          return -1;
          }
          }
          void Rplace_String()
          {
               cout << "Enter String You Want to replace : ";
               cin >> Rplce;
               int i=0;
               while(Rplce[i]!='\0')
               {
                        i++;
                        }           
          str.replace(Find_loca(),i,Rplce);
          cout << str;
         
           }
      };
int main()
{
Find_Locaton lc;
string srch;
cout << "Enter String for serach....";
cin >> srch;
lc.SetSrc(srch);
lc.SetStr("he is a good");

cout << " Location Found :  "<<lc.Find_loca() << endl;
lc.Rplace_String();
getch();
return 0;

}