initial commit

C++/lesson2/task1.cpp

@@ -0,0 +1,13 @@
+#include <iostream>
+
+int main() {
+    int num;
+
+    std::cin >> num;
+
+    for (int i = num; i >= 1; i--) {
+        if (i % 3 == 0) {
+            std::cout << i << '\n';
+        }
+    }
+}

C++/lesson2/task10.cpp

@@ -0,0 +1,17 @@
+#include <iostream>
+#include <string>
+
+int main() {
+    std::string value = std::string();
+    std::cin >> value;
+    int offset;
+    std::cin >> offset;
+    offset = offset % 26 - 'A';
+    for (char& c : value) {
+        if (c > 'Z' || c < 'A') {
+            continue;
+        }
+        c = (c + offset) % 26 + 'A';
+    }
+    std::cout << value << '\n';
+}

C++/lesson2/task2.cpp

@@ -0,0 +1,14 @@
+#include <iostream>
+
+int main() {
+    unsigned sum = 0;
+    while (true) {
+        int i;
+        std::cin >> i;
+        if (i < 0) {
+            break;
+        }
+        sum += i;
+    }
+    std::cout << sum << '\n';
+}

C++/lesson2/task3.cpp

@@ -0,0 +1,12 @@
+#include <iostream>
+
+int main() {
+    const int days[]{31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
+    int month;
+    std::cin >> month;
+    if (month <= 0 || month > 12) {
+        std::cout << "You are a bad person!\n";
+        return 0;
+    }
+    std::cout << days[month - 1] << '\n';
+}

C++/lesson2/task4.cpp

@@ -0,0 +1,17 @@
+#include <iostream>
+
+int main() {
+    int sum = 0;
+    int num;
+    std::cin >> num;
+    if (num < 0) {
+        std::cout << "You are a bad person!\n";
+        return 0;
+    }
+    while (num != 0) {
+        int digit = num % 10;
+        num /= 10;
+        sum += digit;
+    }
+    std::cout << sum << '\n';
+}

C++/lesson2/task5.cpp

@@ -0,0 +1,21 @@
+#include <iostream>
+#include <numeric>
+
+int main() {
+    int a, b;
+    std::cin >> a;
+    std::cin >> b;
+    std::cout << std::lcm(a, b) << '\n';
+    // int guess;
+    // if (a > b) {
+    //     guess = a;
+    // } else {
+    //     guess = b;
+    // }
+    // for (;; guess++) {
+    //     if (guess % a == 0 && guess % b == 0) {
+    //         std::cout << guess << '\n';
+    //         break;
+    //     }
+    // }
+}

C++/lesson2/task6.cpp

@@ -0,0 +1,27 @@
+#include <cmath>
+#include <iostream>
+#include <vector>
+
+int main() {
+    int n;
+    std::cin >> n;
+    if (n < 0) {
+        std::cout << "You are a bad person!\n";
+        return 0;
+    }
+    std::vector<bool> values(n + 1, true);
+    int root = sqrt(n);
+    for (unsigned int i = 2; i <= root; i++) {
+        if (values[i]) {
+            std::cout << i << '\n';
+            for (int j = i * i; j <= n; j += i) {
+                values[j] = false;
+            }
+        }
+    }
+    for (int i = root + 1; i <= n; i++) {
+        if (values[i]) {
+            std::cout << i << '\n';
+        }
+    }
+}

C++/lesson2/task7.cpp

@@ -0,0 +1,21 @@
+#include <iostream>
+#include <string>
+
+int main() {
+    std::string value = std::string();
+    value.reserve(9);
+    for (int count = 4; count >= 0; count--) {
+        value.clear();
+        for (int j = 0; j < count; j++) {
+            value.push_back(' ');
+        }
+        int limit = 9 - count * 2;
+        for (int j = 0; j < limit; j++) {
+            value.push_back('*');
+        }
+        for (int j = 0; j < count; j++) {
+            value.push_back(' ');
+        }
+        std::cout << value << '\n';
+    }
+}

C++/lesson2/task8.cpp

@@ -0,0 +1,36 @@
+#include <iostream>
+#include <string>
+
+int main() {
+    int height;
+    std::cin >> height;
+    std::string value = std::string();
+    for (int count = height - 1; count >= 0; count--) {
+        value.clear();
+        for (int j = 0; j < count; j++) {
+            value.push_back(' ');
+        }
+        int limit = height * 2 - 1 - count * 2;
+        for (int j = 0; j < limit; j++) {
+            value.push_back('*');
+        }
+        for (int j = 0; j < count; j++) {
+            value.push_back(' ');
+        }
+        std::cout << value << '\n';
+    }
+    for (int count = 1; count < height; count++) {
+        value.clear();
+        for (int j = 0; j < count; j++) {
+            value.push_back(' ');
+        }
+        int limit = height * 2 - 1 - count * 2;
+        for (int j = 0; j < limit; j++) {
+            value.push_back('*');
+        }
+        for (int j = 0; j < count; j++) {
+            value.push_back(' ');
+        }
+        std::cout << value << '\n';
+    }
+}

C++/lesson2/task9.cpp

@@ -0,0 +1,23 @@
+#include <iostream>
+
+int main() {
+    unsigned int sum = 0;
+    while (true) {
+        int num;
+        std::cin >> num;
+        if (num == 0) {
+            break;
+        }
+        if (num < 0) {
+            std::cout << "You are a bad person!\n";
+            return 0;
+        }
+        sum += num;
+    }
+    if (sum > 1000) {
+        sum += sum * 2 / 10;
+    } else if (sum < 500) {
+        sum -= sum / 10;
+    }
+    std::cout << sum << '\n';
+}