While loop and for loop 06 (js)
- 1. While Loop And For Loop
- 2. While writing a program, you may encounter a situation where you need to perform an action over and over again. In such situations, you would need to write loop statements to reduce the number of lines. JavaScript supports all the necessary loops to ease down the pressure of programming. The while Loop: The most basic loop in JavaScript is the while loop which would be discussed in this chapter. The purpose of a while loop is to execute a statement or code block repeatedly as long as an expression is true. Once the expression becomes false, the loop terminates. Flow Chart The flow chart of while loop looks as follows −
- 3. Syntax The syntax of while loop in JavaScript is as follows − Example Try the following example to implement while loop.
- 4. Output
- 5. The do...while Loop The do...while loop is similar to the while loop except that the condition check happens at the end of the loop. This means that the loop will always be executed at least once, even if the condition is false. Flow Chart The flow chart of a do-while loop would be as follows −
- 6. Syntax The syntax for do-while loop in JavaScript is as follows − Note − Don’t miss the semicolon used at the end of the do...while loop. Example: Try the following example to learn how to implement a do-while loop in JavaScript.
- 7. Output
- 8. For Loop The 'for' loop is the most compact form of looping. It includes the following three important parts − •The loop initialization where we initialize our counter to a starting value. The initialization statement is executed before the loop begins. •The test statement which will test if a given condition is true or not. If the condition is true, then the code given inside the loop will be executed, otherwise the control will come out of the loop. •The iteration statement where you can increase or decrease your counter. You can put all the three parts in a single line separated by semicolons.
- 9. Flow Chart: The flow chart of a for loop in JavaScript would be as follows − Syntax The syntax of for loop is JavaScript is as follows −
- 10. Example: Try the following example to learn how a for loop works in JavaScript.
- 11. Output