While loop in JavaScript with an example !

Hai everyone. Do you know what is While loop in JavaScript ? …oh,  Now we are going to learn what is While loop for better understanding we take an example !

 

Just in simple words

Repeatedly Excutes statement as long as a given condition is True

The situation when programming is needed to perform a certain action again, again Until certain condition

syntax :

while(Expression needed to be executed){
The Statement that has to be executed, Until the above expression holds the value to false
}

 

Here firstly the while loop evaluates the condition inside(),

If the condition evaluates to True the code inside { } is Executed

Example

let count = 1; // here its Initial value is starting from 1
while(count<=6){      //condition is from initial to until 6
    console.log(count);
    count++     // the count will be incremented
}

output :
1
2
3
4
5
6

• Firstly, The count is Initialized to 1
• The loop runs as long as count is greater than less than and equal to 6
• Inside the loop console.log(count) outputs the current value of count
• After each iteration , count is incremented by 1. (count++)

While loop by taking user input

let num = 0 ,sum=0 ;
while(num >=0){
    sum = num+sum;
    num = parseInt(prompt("enter a number: "));
    console.log(`the sum is ${sum}`);
}

 

In the above program prompts is used to the user to enter a number

• The conditon of loop is if the  num were greater than zero only it will take. when we give negative i won’t allow
• The JavaScript prompts() only takes input as string , parseInt() is used to convert the input to number

As long as we enter a positive number the While loop adds them up and ask us to enter more numbers