while loop with examples in C++

The provided C++ code demonstrates various uses of the while loop, showcasing how it can be utilized for basic iteration, and how control flow statements like break, continue, and return can be integrated within these loops to manage their execution more precisely.

Code

#include <iostream>
using namespace std;

/**
 * Demonstrates various uses of the while loop in C++.
 *
 * This program includes examples of basic while loops, and while loops with control
 * flow statements such as break, continue, and return to manage loop execution.
 */
int main() {
    // Basic while loop example
    int i = 0;
    while (i < 10) {
        cout << i << endl; // Prints numbers from 0 to 9
        i++;
    }
    cout << "Done" << endl; // Indicates the end of the loop

    // While loop with break statement
    i = 0;
    while (i < 10) {
        if (i == 5) {
            break; // Exits the loop when i equals 5
        }
        cout << i << endl; // Prints numbers from 0 to 4
        i++;
    }
    cout << "Done" << endl; // Indicates the end of the loop

    // While loop with continue statement
    i = 0;
    while (i < 10) {
        if (i == 5) {
            i++; // Increment before continue to avoid infinite loop
            continue; // Skips the rest of the loop body when i equals 5
        }
        cout << i << endl; // Prints numbers from 0 to 9, skipping 5
        i++;
    }
    cout << "Done" << endl; // Indicates the end of the loop

    // While loop with return statement
    i = 0;
    while (i < 10) {
        if (i == 5) {
            return 0; // Exits the program when i equals 5
        }
        cout << i << endl; // Prints numbers from 0 to 4
        i++;
    }
    cout << "Done" << endl; // This line is never reached due to the return statement

    return 0;
}

Explanation

The provided C++ code demonstrates various uses of the while loop, showcasing how it can be utilized for basic iteration, and how control flow statements like break, continue, and return can be integrated within these loops to manage their execution more precisely.

Initially, the code presents a basic while loop example where a counter i is incremented in each iteration until it reaches 10. This loop prints numbers from 0 to 9, illustrating the fundamental use of while for repetitive tasks.

int i = 0;
while (i < 10) {
    cout << i << endl;
    i++;
}

Following this, the code explores a while loop that incorporates a break statement. This loop is designed to exit prematurely when i equals 5. Until that point, it functions similarly to the first loop, printing numbers from 0 to 4. The break statement demonstrates how to exit a loop based on a condition, offering a way to halt iteration when a specific criterion is met.

if (i == 5) {
    break;
}

Next, the code introduces a while loop with a continue statement. This loop skips the current iteration when i equals 5, effectively omitting the number 5 from the output. It highlights how continue can be used to skip certain iterations within a loop, based on specific conditions, without exiting the loop entirely.

if (i == 5) {
    i++;
    continue;
}

Lastly, the code features a while loop that employs a return statement to exit not just the loop but the entire program when i equals 5. This example shows how return can be used within a loop to terminate the program execution based on a condition, providing a direct way to control the flow of the program from within iterative structures.

if (i == 5) {
    return 0;
}

Each of these examples serves to illustrate the flexibility and control that while loops offer in C++, enabling developers to manage loop execution with precision through the use of control flow statements.

Output

0
1
2
3
4
5
6
7
8
9
Done
0
1
2
3
4
Done
0
1
2
3
4
6
7
8
9
Done
0
1
2
3
4

Process finished with exit code 0