How to Split a String by Multiple Delimiters in C++?

Last Updated : 22 Feb, 2024

In C++, while working with string manipulation we may sometimes need to split a string into substrings based on multiple delimiters. In this article, we will learn how to split a string by multiple delimiters in C++.

For Example,

Input:
string inputString= "Hello,World;This|is.GeeksForGeeks";
string delimiters = ",;.|";

Output:
Hello
World
This
is
GeeksForGeeks

Split a String into Words by Multiple Delimiters in C++

To split a std::string by multiple delimiters, we can use std::string::find_first_of to search the delimiters in a string with the combination of std::string::substr to extract the substrings.

Approach

Start with startPos = 0 and endPos = 0, run a loop until endPos is not equal to string::npos
Use std::string::find_first_of to find the position of the first occurrence of any delimiter.
If found, use std::string::substr to extract the substring between startPos and the delimiter position found by find_first_of and add it to result.
If not found, extract the substring from startPos to the end of the string and add it to result also set endPos to string::npos to exit the loop.
Repeat the process until the end of the string is reached.

C++ Program to Split a String by Multiple Delimiters

The below example demonstrates how we can split a given string by multiple delimiters in C++.

C++

// C++ Program to split the string by miltiple delimiters

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

// Function to split a string by multiple delimiters
vector<string> splitStringByDelimiters(string& inputString,
                                       string& delimiters)
{

    vector<string>
        result; // Vector to store the split substrings
    int startPos = 0;
    int endPos = 0;

    // Loop until endPos is not equal to string::npos
    while ((endPos = inputString.find_first_of(delimiters,
                                               startPos))
           != string::npos) {

        if (endPos != startPos) { // Checking if the
                                  // substring is non-empty
            result.push_back(inputString.substr(
                startPos, endPos - startPos));
        }

        startPos
            = endPos + 1; // Update startPos to the position
                          // after the delimiter
    }

    // Extract the substring from startPos to the end of the
    // string and add it to result
    if (startPos != inputString.length()) {
        result.push_back(inputString.substr(startPos));
    }
    return result;
}

int main()
{

    // string to be splitted
    string inputString
        = "Hello,World;This|is.GeeksForGeeks";

    // multiple delimiters
    string delimiters = ",;.|";

    // calling the function to split the string using
    // multiple delimiters
    vector<string> substrings
        = splitStringByDelimiters(inputString, delimiters);

    // Displaying the string after splitiing
    for (const auto& substring : substrings) {
        cout << substring << endl;
    }

    return 0;
}

Output

Hello
World
This
is
GeeksForGeeks

Time Complexity: O(n)
Auxiliary Space: O(n) , here m is the number of substrings in the result vector.