Difference Between while and do-while Loop (Full Details)

While loops can be used to execute the same statements for a large number of instances without restriction, The do-while loop, on the other hand, has its uses when it comes to running the same statements a greater number of times and for specific purposes.

What are loops?

A Loop repeats the same set of statements until the condition is no longer true. The body of a loop and a control statement make up a loop. The body of the loop is instructed to run until the provided condition becomes false by the control statement, which is a combination of a few conditions. The loop’s objective is to repeatedly run the same code.

while and do while Loop

While Loop vs. Do-While Loop

While in a while loop, the statement is carried out up to the point where the condition is true and stops as soon as it is false. A Boolean expression may also be used as the while loop’s statement. For instance, if a statement returns a value other than zero, the statement will be true; if it returns zero, the statement will be false. The next line of code is run after the condition is verified to see if it is true. If it is not, the loop repeats itself. A single statement or an empty statement can make up the loop’s body. The while loop passes control to the next statement if the condition is true. If it is stated to print n, ten times, then n, ten times, will be printed if a specific condition is true.

Do-while is a condition that comes at the end of a do-while loop. In while loop, the first iteration is checked, and while loop is run if the first iteration is false. The body of the statement is checked in the do-while loop. The statement comes before the body of the loop, and the conditional statement comes at the end of the loop. The do-while loop can include block or statements or statements that do nothing. The Boolean expression is true for every value that is not zero. In the body of the do-while loop, control is given to the states, and then control is given to the loop’s condition. If the condition is true, the loop will repeat, but if it is false, the control will go to the next line.

What is While Loop?

As long as one claim continues to be true and is independent of any other circumstances, it keeps repeating itself. The sentence construction of a while circle in C++ is: while(situation) (situation) In this case, the assertion is most likely to consist of one or more code strands. The circumstance might be any expression, but it fails if the loop has a value of 0. It must remain positive and higher than one under all conditions. The while loop is used to repeatedly run a portion of code until a condition is met. Say, for example, that we need to determine how frequently we will split a given number that isn’t equal to 1. We keep adding the quantity, and the loop continues to run till the quantity is 1 and it is displayed after the loop is finished. Before performing the circular body, it evaluates the current condition. A minimum of one circle inside another while, for, or do-while statement may be utilized. Until the phrase appears to be false, this motion is repeated. Otherwise, the entire process keeps going round and round. In rare cases, it may cause the system to crash since the value never becomes false and the system continues to function quickly as a result.

What is the Do-While Loop?

If the initial circumstance continues to be true, it remains true; but, if something does not fit the claim, it ceases to be true. The person has more control over it because they can define several loops that could come true if the circumstance applies to them. The following interface is useful for defining the assertion. Do while (situation); If the circumstance is true, this system moves in the direction of the do assertion, and the statement(s) within this system are executed once more. A variant of the while loop is the do/while loop. Before determining whether the condition is legitimate, this process will be done by the code. If the state is appropriate, it should then reappear. The do-while is similar to the while, with the exception that the checking circumstance occurs at the end of the loop. The check situation being at the very end assures that the code doesn’t crash this system and, thus, remains fixed in any case. The code included in the sq. is initially run, and then the state is evaluated. The code inside the bracket is executed once more if the scenario is real. This system is terminated if the circumstance is false.

Comparison Table (While Loop vs. Do-While Loop)

WhileDo While
Prior to executing the statement, it first checks the condition (s)The statement(s) will be run through this loop at least once before the condition is verified.
The while loop enables counter variables to be initialized before the body of the loop begins.Initializing counter variables before and after the body of a loop can be done with a do while loop.
It is a loop with entrance control.This loop has an exit control.
The while condition does not require a semicolon at the end.The while condition must include a semicolon at the conclusion.
We must include brackets when using a single statement.You always need brackets.
The condition is stated in this loop from the very beginning.After the block has been executed, the loop condition is defined.
If the condition is false, a statement (or statements) may be run 0 times.Statement is executed at least once.
while (condition) { Statements; // loop body }do{ Statements; //loop body } while (condition);

Key Differences Between while and do-while Loop

  • The while loop checks the condition at the beginning of the loop and executes the statement inside the loop if the condition is met. In contrast, the condition is tested in the do-while loop after all the statements in the loop’s body have been executed.
  • In a while loop, none of the statements are performed if the condition is false. In contrast, if the do-while loop’s condition is false, the condition is tested before the loop’s body is at least once executed.
  • Because the body of the loop is executed before the condition is checked in the while loop, it is also known as the entry-controlled and pre-checking loop. The exit-controlled and post-checking loop, in contrast, is another name for the do-while loop since the body of the loop is executed after the loop condition has been checked.
  • A semicolon marks the end of the loop in the syntax of a do-while loop. On the other hand, the while loop syntax does not use a semicolon.

Syntax

– The basic format of a while loop is:

while (condition)

{     statement 1;

      statement 2;

      .

      .

      statement(n);

  }

Prior to the statement(s) inside the block executing, the while loop evaluates the condition at its beginning. A condition that is surrounded in parenthesis is followed by statements before the keyword while. The result of the condition must be either True or False.

The basic format of a do-while loop is:

do {

       .

       statements // body of loop;

       } while (condition);

The while keyword and the condition are not coded in this case until after the loop’s body. This implies that we do not need to examine the while condition when entering the loop. Prior to determining the loop condition, it first executes the statements.

Conclusion

While and do-while loops both function as iteration statements, the while loop is employed if we want the statements inside the loop to run after the condition has been confirmed. The do-while loop is utilized if you wish to test the termination condition at the conclusion of the loop.