#include <string>
#include <cctype>   // std::isspace
#include <algorithm>
#include <iostream>

std::string trim(const std::string& s) {
    auto start = std::find_if_not(s.begin(), s.end(), ::isspace);
    auto end = std::find_if_not(s.rbegin(), s.rend(), ::isspace).base();
    return (start < end) ? std::string(start, end) : "";
}

std::string raw = "   \t\n Hello, world! \n ";
std::string cleaned = trim(raw);

std::cout << "[" << cleaned << "]\n";

[Hello, world!]

Оставляю ссылочку: GitHub 📱

std::cout << i << std::endl;

for (int i = 0; i < 100000; ++i) {
    std::cout << i << std::endl;
}

std::cout << i << '\n';

std::vector<double> v = {1.5, 2.5, 3.5};

auto sum = std::accumulate(v.begin(), v.end(), 0);

auto sum = std::accumulate(v.begin(), v.end(), 0.0);

🔊 Продолжай читать на habr!

std::string make_password(std::size_t length) {
    const std::string chars =
        "abcdefghijklmnopqrstuvwxyz"
        "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
        "0123456789"
        "!@#$%^&*";

    std::random_device rd;
    std::mt19937 gen(rd());

    std::uniform_int_distribution<std::size_t> dist(
        0, chars.size() - 1
    );

    std::string result;

    for (std::size_t i = 0; i < length; ++i) {
        result += chars[dist(gen)];
    }

    return result;
}

int main() {
    std::string password = make_password(12);

    std::cout << "Password: " << password << '\n';
}

Password: a7K!pQ2z#Lm9

Base* task = new Task;
delete task;

struct Base {
    virtual void run() = 0;
};

struct Base {
    virtual ~Base() = default;
    virtual void run() = 0;
};

FILE* f = std::fopen(path, "rb");
if (!f) return;

do_work(f);

if (something_bad()) {
    std::fclose(f);     // легко забыть
    return;
}

std::fclose(f);

using FilePtr = std::unique_ptr<FILE, decltype(&std::fclose)>;

FilePtr f(std::fopen(path, "rb"), &std::fclose);
if (!f) return;

do_work(f.get());

if (something_bad()) {
    return; // fclose вызовется сам
}

FilePtr open_file(const char* path, const char* mode) {
    return FilePtr(std::fopen(path, mode), &std::fclose);
}

auto f = open_file(path, "rb");
if (!f) return;