C++primer 9.43

题目要求：编写一个函数，接受三个string参数s,oldVal和newVal。使用迭代器及insert和erase函数将s中所有oldVal替换为newVal。测试你的程序，用它替换通用的简写形式，如，将"tho"替换为"though"，将"thru"替换为"though"。

#include<iostream>
#include<string>
#include<vector>
#include<sstream>
using namespace std;

void find_replace(string s, string oldValue, string newValue)
{	
	if (s.empty() || oldValue.empty() || newValue.empty())
	{
		cout << "Error" << endl;
		return;
	}
	if (s.size() < newValue.size())
	{
		cout << "Error" << endl;
		return;
	}

	string word;
	vector<string>vec;

	//分割string
	istringstream stream(s);
	{
		while(stream >> word)
		   vec.push_back(word);
	}


	vector<string>::iterator it1 = vec.begin();

	while (it1 != vec.end())
	{
		if (*it1 == oldValue)
		{
			string::iterator it2 = (*it1).begin();
			it2 = (*it1).erase(it2, it2+oldValue.size());
			(*it1).insert(it2, newValue.begin(), newValue.end());
		}
		else
		{
			string::iterator it3 = (*it1).begin();
			string::iterator it4 = oldValue.begin();
			while (it3 != (*it1).end())
			{
				if ((*it3) == (*it4))
				{
					string sub = (*it1).substr(it3-(*it1).begin(), oldValue.size());
					if (sub == newValue)
					{
						unsigned offset = it3 - (*it1).begin();
						it3 = (*it1).erase(it3, it3+oldValue.size());
						(*it1).insert(it3, newValue.begin(), newValue.end());
						it3 = (*it1).begin() + offset + newValue.size() - 1;
					}
				}
				it3++;
			}
		}
		it1++;
	}

	for (auto i = vec.begin(); i != vec.end(); i++)
		cout << *i << endl;

}

int main()
{
	//略

	return 0;
}