01_reduce_example.js

const vect = ['h','e','l','l','o',' ','w','o','r','l','d'];

const newString = vect.reduce((acc, character) => acc.concat(character));

console.log(newString); //hello world

02_accumulate_example.cpp

#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <numeric>

int main(){
    std::vector<char> vect {'h','e','l','l','o',' ','w','o','r','l','d'};

    std::string result = std::accumulate(vect.begin(), vect.end(), std::string(),
            [](std::string acc, char character){return acc + character;});

    std::cout << result; //hello world
}