Split a string into substrings of equal length in C++

This post will discuss how to split a string into substrings of equal length in C++.

1. Using `string::substr` function

The substr() function is one of the simplest and most straightforward methods to split a string into substrings of equal length. It returns a copy of a substring of the string, starting from a given position and having a given length. It takes one or two parameters: the position of the first character of the substring, and optionally, the length of the substring. It can be used as follows to split a string into substrings of equal length:

#include <iostream>

#include <string>

#include <vector>

int main()

{

std::string str = "abcdefg";

int mid = (str.length() + 1) / 2;

std::string first = str.substr(0, mid);

std::string second = str.substr(mid);

std::cout << first << std::endl; // abcd

std::cout << second << std::endl; // efg

return 0;

}

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2. Using `std::string` constructor

Alternatively, we can use the range constructor of std::string to split a string into substrings of equal length. For example:

#include <iostream>

#include <string>

#include <vector>

int main()

{

std::string str = "abcdefg";

auto mid = str.begin() + (str.size() + 1) / 2;

std::string first(str.begin(), mid);

std::string second(mid, str.end());

std::cout << first << std::endl; // abcd

std::cout << second << std::endl; // efg

return 0;

}

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3. Using Regular Expressions

To split a string into substrings of equal length, we can create a regular expression pattern that matches any n characters in the string, where n is the number of substrings. Then, we can use a loop to iterate over the matches of the pattern in the string using regex_iterator and track each match as a substring. For example:

#include <iostream>

#include <string>

#include <iterator>

#include <regex>

int main()

{

std::string str = "abcdefg";

int n = (str.length() + 1) / 2;

// Create a regular expression pattern that matches any n characters

std::regex pattern(".{0," + std::to_string(n) + "}");

// Use a loop to iterate over the matches of the pattern in the string

// using regex_iterator

auto it = std::sregex_iterator(str.begin(), str.end(), pattern);

while (it != std::sregex_iterator())

{

// display each match as a substring

std::cout << it->str() << std::endl;

it++;

}

return 0;

}

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That’s all about splitting a string into substrings of equal length in C++.

Split a string into substrings of equal length in C++

1. Using string::substr function

2. Using std::string constructor

3. Using Regular Expressions

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1. Using `string::substr` function

2. Using `std::string` constructor