All About Strings.

#include <iostream>
#include <string>
using namespace std;
string fstringfinder(string start, string end, string search)
{
string return_value;

int start_loc = (int) search.find(start,0); //find the location of the starting string
int end_loc = (int) search.find(end,0); //find location of ending string
int len_substr = end_loc - start_loc  + 1; //the length of the new string
if ((end_loc < start_loc) || (start_loc < 0) || (end_loc < 0)) 
//error - either the starting string is after the ending one, or one 
//of the 2 strings is not found in the searched string
return "Error!"; //good idea to be substituted with something more practical, like a list of error codes.
else
return_value= search.substr(start_loc,len_substr);
return return_value;
}


int main()
{
string a("0123456789");
cout << fstringfinder("4","7",a);
return 0;