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While and Do-While Loop in C++

while Loop​

A while loop in C++ repeatedly executes a block of statements as long as a specified condition is true. The condition is evaluated before the execution of the loop's body.

Do While Loop

Flowchart of while Loop​

      +----------------------+
      |      Start           |
      +----------------------+
                |
                v
      +----------------------+
      |  Condition?          |
      +----------------------+
         |          |
         |          v
      True         False
         |          |
         v          v
+----------------+  |
|  Loop Body     |  |
+----------------+  |
         |          |
         +----------+
                |
                v
      +----------------------+
      |      End             |
      +----------------------+

Example 1: Display Numbers from 1 to 5​

#include <iostream>

int main() {
    int i = 1;
    while (i <= 5) {
        std::cout << i << std::endl;
        i++;
    }
    return 0;
}

do...while Loop​

A do...while loop in C++ is similar to a while loop, except that the condition is evaluated after the execution of the loop's body. This guarantees that the loop body is executed at least once.

Flowchart of do...while Loop​

      +----------------------+
      |      Start           |
      +----------------------+
                |
                v
      +----------------------+
      |  Loop Body           |
      +----------------------+
                |
                v
      +----------------------+
      |  Condition?          |
      +----------------------+
         |          |
         |          v
      True         False
         |          |
         v          v
+----------------+  |
|  Loop Body     |  |
+----------------+  |
         |          |
         +----------+
                |
                v
      +----------------------+
      |      End             |
      +----------------------+

Example 2: Display Numbers from 1 to 5​

#include <iostream>

int main() {
    int i = 1;
    do {
        std::cout << i << std::endl;
        i++;
    } while (i <= 5);
    return 0;
}