Split string in C++ using a delimiter

This post will discuss how to split a string in C++ using a delimiter and construct a vector of strings containing individual strings.

C++ standard library didn’t provide any built-in function for this concrete task. This post provides an overview of some of the available alternatives to accomplish this.

1. Using `find_first_not_of()` with `find()` function

We can use a combination of string’s find_first_not_of() and find() functions to split a string in C++, as shown below:

#include <iostream>

#include <string>

#include <vector>

void tokenize(std::string const &str, const char delim,

std::vector<std::string> &out)

{

size_t start;

size_t end = 0;

while ((start = str.find_first_not_of(delim, end)) != std::string::npos)

{

end = str.find(delim, start);

out.push_back(str.substr(start, end - start));

}

int main()

{

std::string s = "C*C++*Java";

const char delim = '*';

std::vector<std::string> out;

tokenize(s, delim, out);

for (auto &s: out) {

std::cout << s << std::endl;

}

return 0;

}

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Output:

C
C++
Java

2. Using `getline()` function

Another good alternative is to use the std::getline function, which extracts characters from the istream object and stores them into a specified stream until the delimitation character is found.

#include <iostream>

#include <string>

#include <vector>

#include <sstream>

void tokenize(std::string const &str, const char delim,

std::vector<std::string> &out)

{

// construct a stream from the string

std::stringstream ss(str);

std::string s;

while (std::getline(ss, s, delim)) {

out.push_back(s);

}

int main()

{

std::string s = "C*C++*Java";

const char delim = '*';

std::vector<std::string> out;

tokenize(s, delim, out);

for (auto &s: out) {

std::cout << s << std::endl;

}

return 0;

}

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Output:

C
C++
Java

3. Using `std::regex_token_iterator` function

Another solution is to use the std::sregex_token_iterator which is a specialization of std::regex_token_iterator<std::string::const_iterator>

#include <iostream>

#include <regex>

#include <string>

int main()

{

std::string s = "C*C++*Java";

std::regex regex("\\*");

std::vector<std::string> out(

std::sregex_token_iterator(s.begin(), s.end(), regex, -1),

std::sregex_token_iterator()

);

for (auto &s: out) {

std::cout << s << std::endl;

}

return 0;

}

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Output:

C
C++
Java

4. Use `std::strtok` function

We can also use the strtok() function to split a string into tokens, as shown below:

#include <iostream>

#include <string>

#include <vector>

#include <cstring>

void tokenize(std::string const &str, const char* delim,

std::vector<std::string> &out)

{

char *token = strtok(const_cast<char*>(str.c_str()), delim);

while (token != nullptr)

{

out.push_back(std::string(token));

token = strtok(nullptr, delim);

}

int main()

{

std::string s = "C*C++*Java";

const char* delim = "*";

std::vector<std::string> out;

tokenize(s, delim, out);

for (auto &s: out) {

std::cout << s << std::endl;

}

return 0;

}

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Output:

C
C++
Java

5. Using `std::string::find` function

Finally, we can use std::string::find algorithm with std::string::substr which is demonstrated below:

#include <iostream>

#include <string>

#include <vector>

#include <algorithm>

void tokenize(const std::string &s, const char delim,

std::vector<std::string> &out)

{

std::string::size_type beg = 0;

for (auto end = 0; (end = s.find(delim, end)) != std::string::npos; ++end)

{

out.push_back(s.substr(beg, end - beg));

beg = end + 1;

}

out.push_back(s.substr(beg));

}

int main()

{

std::string s = "C*C++*Java";

const char delim = '*';

std::vector<std::string> out;

tokenize(s, delim, out);

for (auto &s: out) {

std::cout << s << std::endl;

}

return 0;

}

Download Run Code

Output:

C
C++
Java

That’s all about splitting a string in C++ using a delimiter.

Split string in C++ using a delimiter

1. Using find_first_not_of() with find() function

2. Using getline() function

3. Using std::regex_token_iterator function

4. Use std::strtok function

5. Using std::string::find function

Share this:

1. Using `find_first_not_of()` with `find()` function

2. Using `getline()` function

3. Using `std::regex_token_iterator` function

4. Use `std::strtok` function

5. Using `std::string::find` function