C++ Programming Tutorial

#include <iostream>

int main() {
    // Fixed-size, stack-allocated
    int numbers[5] = {10, 20, 30, 40, 50};

    // Access by index (0-based)
    std::cout << numbers[0] << "
";  // 10
    std::cout << numbers[4] << "
";  // 50

    // Iterate
    for (int i = 0; i < 5; ++i) {
        std::cout << numbers[i] << " ";
    }
    std::cout << "
";

    // WARNING: no bounds checking!
    // numbers[10] = 99;  // undefined behavior — may crash or corrupt memory

    // Size must be known at compile time
    constexpr int SIZE = 3;
    double values[SIZE] = {1.1, 2.2, 3.3};

    return 0;
}

#include <iostream>
#include <array>
#include <algorithm>

int main() {
    // Type-safe, knows its own size, supports STL algorithms
    std::array<int, 5> nums{10, 20, 30, 40, 50};

    std::cout << "Size: " << nums.size() << "
";   // 5
    std::cout << "First: " << nums.front() << "
"; // 10
    std::cout << "Last: " << nums.back() << "
";   // 50

    // Bounds-checked access with .at()
    // nums.at(10);  // throws std::out_of_range

    // Works with algorithms
    std::sort(nums.begin(), nums.end());
    std::reverse(nums.begin(), nums.end());

    // Range-based for
    for (int n : nums) {
        std::cout << n << " ";
    }
    std::cout << "
";

    return 0;
}

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

int main() {
    // Create and initialize
    std::vector<int> nums{1, 2, 3, 4, 5};
    std::vector<std::string> names{"Alice", "Bob", "Charlie"};
    std::vector<double> zeros(10, 0.0);  // 10 elements, all 0.0

    // Add elements
    nums.push_back(6);
    nums.push_back(7);
    nums.emplace_back(8);  // construct in-place (more efficient)

    // Access elements
    std::cout << nums[0] << "
";      // 1 (no bounds check)
    std::cout << nums.at(2) << "
";   // 3 (throws if out of range)
    std::cout << nums.front() << "
"; // 1
    std::cout << nums.back() << "
";  // 8

    // Size and capacity
    std::cout << "Size: " << nums.size() << "
";
    std::cout << "Empty: " << nums.empty() << "
";

    // Remove elements
    nums.pop_back();  // remove last
    nums.erase(nums.begin() + 1);  // remove at index 1

    // Insert
    nums.insert(nums.begin(), 0);  // insert 0 at front

    // Iterate
    for (const auto& n : nums) {
        std::cout << n << " ";
    }
    std::cout << "
";

    // Sort
    std::sort(nums.begin(), nums.end());

    // Find
    auto it = std::find(nums.begin(), nums.end(), 5);
    if (it != nums.end()) {
        std::cout << "Found 5 at index " << (it - nums.begin()) << "
";
    }

    return 0;
}

#include <iostream>
#include <vector>
#include <numeric>    // for accumulate
#include <algorithm>  // for sort, min/max_element, count

int main() {
    std::vector<int> v{5, 2, 8, 1, 9, 3, 7};

    // Sum all elements
    int sum = std::accumulate(v.begin(), v.end(), 0);
    std::cout << "Sum: " << sum << "
";  // 35

    // Min and max
    auto [min_it, max_it] = std::minmax_element(v.begin(), v.end());
    std::cout << "Min: " << *min_it << ", Max: " << *max_it << "
";

    // Count occurrences
    int count = std::count(v.begin(), v.end(), 5);

    // Remove duplicates (sort first)
    std::sort(v.begin(), v.end());
    v.erase(std::unique(v.begin(), v.end()), v.end());

    // Filter: keep only values > 3
    std::vector<int> filtered;
    std::copy_if(v.begin(), v.end(), std::back_inserter(filtered),
                 [](int x) { return x > 3; });

    for (int n : filtered) std::cout << n << " ";  // 5 7 8 9
    std::cout << "
";

    return 0;
}