Search and Replace Function

#include <string>#include <algorithm>#include <functional>#include <iterator>//Searches the container 'SearchHere' for 'FindThis' and replaces it with 'Replacement'//The predicate 'Pred' is used to compare elements in the container for equality,//   and impose an equivalence relation between its operands.template <typename ContainerType, typename PredicateType>ContainerType FindAndReplace(const ContainerType &p_SearchHere,	const ContainerType &p_FindThis, const ContainerType &p_Replacement,	PredicateType p_Pred){	//Constants to store various boundaries	const ContainerType::const_iterator FindThisBegin = p_FindThis.begin();	const ContainerType::const_iterator FindThisEnd = p_FindThis.end();	const ContainerType::size_type FindThisSize = p_FindThis.size();	const ContainerType::const_iterator ReplacementBegin = p_Replacement.begin();	const ContainerType::const_iterator ReplacementEnd = p_Replacement.end();	const ContainerType::const_iterator SearchHereBegin = p_SearchHere.begin();	const ContainerType::const_iterator SearchHereEnd = p_SearchHere.end();	//Iterators to step through the 'SearchHere' string	ContainerType::const_iterator SearchStart = SearchHereBegin;	ContainerType::const_iterator FoundPosition = SearchStart;	//Container to store the original container with replacements	ContainerType Result;	//Back Inserter Iterator to append elements to Result	std::back_insert_iterator<ContainerType> ResultInserter = std::back_inserter(Result);	do{		//Find the next match in 'SearchHere'		FoundPosition = std::search(SearchStart, SearchHereEnd, FindThisBegin, FindThisEnd, p_Pred);		//Copy the text between the last match and this match		std::copy(SearchStart, FoundPosition, ResultInserter);		//Advance the start position to this match		SearchStart = FoundPosition;		//If there was a match,		if(SearchStart != SearchHereEnd)		{			//Copy the replacement string instead of the match			std::copy(ReplacementBegin, ReplacementEnd, ResultInserter);			//Advance past this match so it won't be found again			std::advance(SearchStart, FindThisSize);		}		//Otherwise, exit loop	}while(FoundPosition != SearchHereEnd);	//Return original container with replacements made	return Result;}//Searches the container 'SearchHere' for 'FindThis' and replaces it with 'Replacement'//The predicate 'std::equal_to' is used to compare elements in the container for equality,//   and impose an equivalence relation between its operands.template <typename ContainerType>ContainerType FindAndReplace(const ContainerType &p_SearchHere,	const ContainerType &p_FindThis, const ContainerType &p_Replacement){	//If no predicate is given, use std::equal_to instead	return FindAndReplace(p_SearchHere, p_FindThis, p_Replacement, std::equal_to<ContainerType::value_type>());}

#include <iostream>using namespace std;int main(void){	string SomeText = "Replace all instances of 'a' with four, except for those instances followed by an 'n', which become '@' instead.";		cout << "Before:" << endl << SomeText << endl << endl;	SomeText = FindAndReplace<string>(SomeText, "an", "@n");	cout << "Between:" << endl << SomeText << endl << endl;	SomeText = FindAndReplace<string>(SomeText, "a", "4");	cout << "After:" << endl << SomeText << endl << endl;	return 0;}