C++: how to Split any String

Splitting an String in C++ may seem difficult if you come from a language like Python, Java, or Go, but it’s actually really easy to implement a function that works just like those languages:

#include <string>
#include <vector>

std::vector<std::string> split(std::string s, std::string delimiter) {
    if (s.find(delimiter) == std::string::npos) {
        return std::vector<std::string> {s};
    }

    std::vector<std::string> s_parts {};
    size_t pos {0};
    std::string token {};
    while ((pos = s.find(delimiter)) != std::string::npos) {
        token = s.substr(0, pos);
        s_parts.push_back(token);
        s.erase(0, pos + delimiter.length());
    }
    s_parts.push_back(s.substr(0));

    return s_parts;
}

As we see, this function takes care of no delimiters in the String, returning just a vector with the original String in it. If the String contains the delimiter, then it will Split it just like it should: returning a vector of all the Strings separated by the chosen delimiter.

You can try this code as follows and see the results for yourself:

#include <iostream>
#include <string>
#include <vector>

std::vector<std::string> split(std::string s, std::string delimiter) {
    if (s.find(delimiter) == std::string::npos) {
        return std::vector<std::string> {s};
    }

    std::vector<std::string> s_parts {};
    size_t pos {0};
    std::string token {};
    while ((pos = s.find(delimiter)) != std::string::npos) {
        token = s.substr(0, pos);
        s_parts.push_back(token);
        s.erase(0, pos + delimiter.length());
    }
    s_parts.push_back(s.substr(0));

    return s_parts;
}

void print_vector(std::vector<std::string> vec) {
    std::string vec_str {};
    vec_str += "[ ";
    for (const auto &s : vec) {
        vec_str += "\"" + s + "\",";
    }
    vec_str.pop_back(); // remove last comma
    vec_str += " ]";
    std::cout << vec_str << std::endl;
}

int main() {
    std::string s1 {"How are you doing"};
    std::string s2 {"How are you doing "};
    std::string s3 {"file"};
    std::string s4 {"file.pdf"};
    std::string s5 {"file.pdf.OLD"};
    std::string s6 {"file.pdf.OLD."};
    std::string s7 {".file.pdf.OLD."};

    print_vector(split(s1, " "));
    print_vector(split(s2, " "));
    print_vector(split(s3, "."));
    print_vector(split(s4, "."));
    print_vector(split(s5, "."));
    print_vector(split(s6, "."));
    print_vector(split(s7, "."));
}

Note that this functions works with single character strings or with multiple character strings: