20+ Difference between For Loop And While Loop

The main difference between a for loop and a while loop lies in their structure and how they iterate through code.

A for loop is a control flow statement that allows executing a block of code repeatedly for a specified number of times. On the other hand, a while loop continues executing a block of code as long as a certain condition remains true.

While loops provide more flexibility in controlling the loop’s termination, loops are generally used when the number of iterations is known beforehand.

For Loop vs While Loop: Comparison

ParameterFor LoopWhile Loop
DefinitionJava has two for loop iterations: standard and for-each, offering flexibility and choice in programming.The while loop is a crucial control structure in C++ and Java, sharing similarities in implementation.
InitializationLoop initialization can happen within or outside the loop, leading to various interpretations.If possible, move initialization outside the main loop for better code organization and efficiency.
IncrementThe increment takes effect after the code finishes executing, not during it.When to execute price increase before or after statement completion & based on efficiency.
UsesUsing this method may work, but calculating repetitions is crucial. Success is possible but not guaranteed.Use this tool to estimate the best iteration frequency when unsure about the exact number of iterations needed.
Iteration statementThe ‘for’ loop’s iteration statement is always placed at the end, executed after all other loop statements.While loop allows condition-based repetitive execution, offering flexibility throughout the process

What Is For Loop?

A for loop is a control flow statement in programming that allows you to execute a block of code a specified number of times or iterate over a sequence of values.

It allows you to automate repetitive processes by setting the starting and finishing points for each iteration and the increment or decrement number.

A for loop’s syntax normally consists of three parts: initialization, condition, and iteration. The initialization assigns a value to the loop variable, the condition decides whether or not the loop should continue, and iteration updates the loop variable after each iteration.

A for loop in many computer languages has the following general structure:

Syntax
for (initialization; condition; iteration)
{
// code to be executed repeatedly
}

The initialization portion is only run once at the start of the loop. Before each iteration, the condition is checked, and the code block is run if it is true.

The iteration section is run after each iteration to update the loop variable. This step is repeated until the condition is no longer true.

Key Difference: For Loop

  • 1 Akin to an assignment statement, the initialization gets things going. A loop control variable may be initialized using this. 
  • 2 A phrase of a relational nature is used as the condition. When this condition is met, the loop will terminate. 
  • 3 A block of statements or no statements may be placed within the for loop’s body. The iteration statement is written at the beginning of a ‘for’ loop. 
  • 4 This means that the iteration statement won’t be run until after everything else has finished. Initialization is only done once in the ‘for’ loop. 
  • 5 If the ‘for’ loop’s condition isn’t met, the loop will keep repeating forever. The ‘for’ statement should be used instead of the ‘while’ statement if you have a certain number of iterations in mind. 
  • 6 The for loop’s conditional statement, initialization, and iteration are all written on top of the loop. Each iteration of the for loop causes the condition to be evaluated. 
  • 7 The for loop’s controlling variable is initialized once, and only once, throughout the loop’s execution. This occurs on the first pass through a loop. 
  • 8 The initialization condition is fulfilled before the condition is verified each time the loop instruction is carried out.
Example Of For Loop
for (int i = 1; i <= 10; i++)
{
System.out.println(i);
}
where to use for loop

What Is While Loop?

In computer programming, a while loop is a control flow statement that is used to execute a block of code continuously until a given condition is met. It enables you to design a loop that will continue once a specified condition is met.

The while loop comprises three basic parts: the keyword “while,” a condition evaluated before each loop iteration, and a piece of code performed as long as the condition is true. Any expression that evaluates to true or false can be used as the condition.

The syntax of a while loop is straightforward:

Syntax
while (condition)
{
// code to be executed repeatedly
}

Key Difference: While Loop

  • 1 Only the while loop’s condition is checked and initialized outside the loop. The’ while’ loop is the best option without a hard-coded limit on the number of loop iterations. 
  • 2 A compilation error will be produced if the condition is missing from the ‘while’ loop. 
  • 3 In case the initialization is performed at the step of condition testing, like in the case of the ‘while’ loop. Each iteration of the loop requires a fresh round of setup. 
  • 4 The statement to be executed during each iteration of the ‘while’ loop may be written at any point inside the loop. Any kind of phrase may be used as the ‘while’ loop’s condition. 
  • 5 If a value other than zero is returned, then it is true. While the specified condition is true, the loop will continue to execute. 
  • 6 Whenever the condition of the loop is no longer true, execution will go to the next line of code in the program. 
  • 7 The while loop performs an initial condition check and then runs the statements inside it until the condition is no longer true. 
  • 8 Any boolean expression may be used for the while loop’s associated criteria. If a value other than zero is returned, the condition holds true; otherwise, it is false.
Example Of While Loop
int i = 0;
while (i < 5)
{
System.out.println(i); i++;
}

How Is For Loop Different From While Loop?

Meaning:

  • For Loop – Using a for loop allows for a clear and succinct structure in a computer programming language.

    In other words, it’s a statement used to regulate admission into a database. The for loop is used to execute a statement several times.

    They help keep the code sizes down. The for loop tests the specified condition iteratively, and execution continues until the goal is achieved.
  • While Loop – Using a while loop is another option for recreating the results of a previous statement’s execution.

    The number of times this loop will iterate is essentially unbounded as long as the goal or condition specified in the given statement has not been reached. The language that is used to construct computer programs has a very fundamental loop in its syntax.

Description:

  • For Loop – First, you write the statements that do any necessary setup, condition checking, and iteration. It’s only useful if you know exactly how many iterations you’ll need.

    An unlimited number of times will be cycled through the loop if the condition is not specified in the ‘for’ statement.

    There is only ever a single round of initialization performed. The statement of iteration is presented first. Therefore, it runs after the loop’s statements have finished executing.
  • While Loop – At the start of the loop, we do any necessary setup and condition testing. Only when the total number of iterations is unknown is this method used.

    The compilation will fail if the condition is not specified inside the ‘while’ loop. If initialization is performed when the condition is verified, it will be executed at each iteration of the loop. Any part of the loop is OK for inserting the iteration statement.

How it works:

  • For Loop – During each iteration of the loop, the initialization condition is executed before the condition itself is checked for accuracy.

    The loop’s body is executed, and then the iteration statement is carried out, but only if the condition has a positive evaluation.

    Going all the way back to the beginning, the condition is examined once more to determine whether or not the loop will remain active or exit.
  • While Loop – First, the condition that controls the loop’s initialization is executed, and only after that is the condition itself put to the test.

    Assuming all preconditions are met, the iteration statement is run first. The condition is rechecked to see whether the loop will continue to repeat as normal or if it will exit the loop.

Where to use:

  • For Loop – Following the completion of the execution of the iteration statement inside the main body of the execution of the for loop, the execution of the iteration statement will begin within the upcoming step of the loop.

    This will take place once the execution of the iteration statement that is included inside the main body of the for loop’s execution has reached its conclusion.
  • While Loop – However, loops allow iteration statements to be placed anywhere in their bodies, which means that subsequent statements in the loop’s body can run after the iteration statement has finished executing.

    This contrasts loops, which do not permit iteration statements to be placed anywhere in their bodies. For loops, on the other hand, which do not allow iteration statements to be put anywhere in their bodies, this is in contrast.
where to use while loop

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comparison between for loop and while loop

Frequently Asked Questions (FAQs)

In a loop, can I use a break or continue statement?

Both break and continue statements are valid in for and while loops. The break command terminates the loop completely, but the continue statement skips the current iteration and moves on to the next iteration.

Can I use a boolean variable as a condition in a for loop or while loop?

Yes, you can use a boolean variable as a condition in both for loops and while loops. The loop will continue executing as long as the boolean condition evaluates to true.

You can update the boolean variable within the loop body or use other logical operators to modify the condition.

Is it possible to exit a loop before it reaches its termination condition?

Yes, using the break statement, you can exit a loop before it reaches its termination condition.

When the break statement is encountered within a loop, the loop is immediately terminated, and the program execution continues with the statement following the loop.

difference between for loop and while loop

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