gistfile1.cpp

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

int main() {
    std::string s = "13579";
    int result = 0;
    std::for_each(s.begin(), s.end(), [&](char n){result = result * 10 + n - '0'; });

    std::cout << result << std::endl;

    std::vector<int> v;
    std::transform(s.begin(), s.end(), std::back_inserter(v), [](char n){ return n - '0';});
    int x = 0;
    std::for_each(v.begin(), v.end(), [&](int y){x = x * 10 + y;});
    std::cout << x << std::endl;
    
    std::cout << std::accumulate(s.begin(), s.end(), 0, [](int x, char y){ return x * 10 + y - '0';}) << std::endl;

    std::vector<int> v2;
    std::transform(s.begin(), s.end(), std::back_inserter(v2), [](char n){ return n - '0';});
    std::cout << std::accumulate(v2.begin(), v2.end(), 0, [](int x, int y){ return x * 10 + y;}) << std::endl;

    return 0;
}