Loops

Loops allow you to execute a block of code repeatedly, making them perfect for repetitive tasks and reducing code duplication.

In C++, we mainly use three types of loops:

  1. for loop
  2. while loop
  3. do-while loop

Let's explore each one in more detail!

The for Loop

The for loop is ideal when you know how many times you want the loop to run. Its syntax includes an initialization, a condition, and an update statement.

Example

#include <iostream>

int main() {
    for (int i = 0; i < 5; i++) {
        std::cout << "Iteration: " << i << std::endl;
    }
}

This loop will print the numbers from 0 to 4. The variable i is initialized with a value of 0, and as long as i < 5, the code inside the loop will execute, incrementing i by one after each iteration (using i++).

The while Loop

The while loop is great when you don't know how many times the loop should run, but you do have a condition that determines when it should stop.

Example

#include <iostream>

int main() {
    int number = 1;

    while (number <= 10) {
        std::cout << "Number: " << number << std::endl;
        number++;
    }
    
    return 0;
}

This loop prints the numbers from 1 to 10. As long as the condition number <= 10 is true, the loop will keep executing and incrementing number.

The do-while Loop

The do-while loop is similar to the while loop, but with one key difference: it always executes the code inside the loop at least once, even if the condition is false from the start.

Example

#include <iostream>

int main() {
    int number;

    do {
        std::cout << "Enter a number between 1 and 10: ";
        std::cin >> number;
    } while (number < 1 || number > 10);

    std::cout << "You entered a valid number: " << number << std::endl;

    return 0;
}

In this example, we prompt the user for a number between 1 and 10. If they enter an invalid value, we continue asking until they provide a valid one. The code inside the loop will always execute at least once, ensuring that we have a valid input before moving on.

Go ahead and experiment with different types of loops to find out which one works best for your specific needs.