문자열 자르기 substr / istringstream / stringstream / strtok

문자열이 주어졌을 때, 공백 단위로 단어를 나누는 방법

ex) 문자열 "apeach frodo muzi" 을 "apeach", "frodo", "muzi" 로 나누어 저장

단어 갯수를 알 경우

1. substr

2. istringstream

단어 갯수를 모를 경우

3. stringstream

4. strtok

1. substr

#include <iostream>
#include <vector>

using namespace std;

int main()
{
	string str = "apeach frodo muzi";
	vector<string> names;

	for (int i = 0; i < 3; i++)
	{
		names.push_back(str.substr(0, str.find(" ")));
		str = str.substr(str.find(" ") + 1);
	}

	for (auto name : names)
	{
		cout << name << endl;
	}

	return 0;
}

2. istringstream

#include <iostream>
#include <vector>
#include <sstream>

using namespace std;

int main()
{
	string str = "apeach frodo muzi";
	vector<string> names;
	istringstream iss(str);
	for (int i = 0; i < 3; i++)
	{
		string tmp;
		iss >> tmp;
		names.push_back(tmp);
	}

	for (auto name : names)
	{
		cout << name << endl;
	}

	return 0;
}

3. stringstream

#include <iostream>
#include <vector>
#include <sstream>

using namespace std;

int main()
{
	string str = "apeach frodo muzi";
	vector<string> names;
	stringstream ss(str);
	string token;
	while (ss >> token)
	{
		names.push_back(token);
	}

	for (auto name : names)
	{
		cout << name << endl;
	}

	return 0;
}

4. strtok

#include <iostream>
#include <vector>

using namespace std;

int main()
{
	string str = "apeach frodo muzi";
	vector<string> names;

	vector<char> w(str.begin(), str.end());
	w.push_back('\0');

	char* ch = &w[0];
	char* context = NULL;
	char* tok = strtok_s(ch, " ", &context);

	while (tok != nullptr)
	{
		names.push_back(string(tok));
		tok = strtok_s(nullptr, " ", &context);
	}

	for (auto name : names)
	{
		cout << name << endl;
	}

	return 0;
}