1.#include using namespace std;int main() {float salary;cout << "Enter salary: ";cin >> salary;if (salary >= 20000)salary *= 0.93; // deduct 7%else if (salary >= 10000)salary -= 1000;cout << "Net salary: " << salary << endl;return 0;}2.#include using namespace std;int main() {float weight, height;cout << "Enter weight (kg): ";cin >> weight;cout << "Enter height (m): ";cin >> height;float bmi = weight / (height * height);cout << "BMI: " << bmi << endl;if (bmi < 18.5)cout << "Underweight\n";else if (bmi < 25)cout << "Normal weight\n";else if (bmi < 30)cout << "Overweight\n";elsecout << "Obese\n";return 0;}3.#include using namespace std;int main() {int number;cout << "Enter a number: ";cin >> number;for (int i = 1; i <= 20; ++i) {for (int j = 1; j <= 10; ++j) {cout << number * (i - 1) + j << " ";}cout << endl;}return 0;}4.#include using namespace std;int main() {for (int i = 1; i <= 20; ++i) {for (int j = i; j < 20; ++j)cout << " ";for (int k = 1; k <= (2 * i - 1); ++k)cout << "X";cout << endl;}return 0;}5.#include using namespace std;int main() {int size;cout << "Enter the size of the chessboard: ";cin >> size;for (int i = 0; i < size; ++i) {for (int j = 0; j < size; ++j) {if ((i + j) % 2 == 0)cout << "*";elsecout << "#";}cout << endl;}return 0;}