C++ equivalent of Java StringUtils.indexOfDifference

Question

For C++20, is there a library equivalent of Java's StringUtils.indexOfDifference()?

What is the efficient way of comparing two large strings and determining where they differ?

Answer 1

You can use std::mismatch from <algorithm>

Returns the first mismatching pair of elements from two ranges

For example

#include <algorithm>
#include <iostream>
#include <iterator>
#include <string>

std::size_t IndexOfDifference(std::string const& lhs, std::string const& rhs) {
    auto diff = std::mismatch(lhs.begin(), lhs.end(), rhs.begin());
    return std::distance(lhs.begin(), diff.first);
}

int main() {
    std::cout << IndexOfDifference("foobar", "foocar");
}

Will output

3