JavaScript Increment & Decrement Operator

```var x = 10;
var x = x++;
var x = ++x;
console.log(x);
*output*
11```
```var x = 10;
var x;
var x = ++x;
console.log(x);

*output*
11   (If you are not clear, dont worry, we will explain this in this post as well)
```
```var x = 10;
var y = x++;
var z = ++x;
console.log(x,y,z);

12 10 12```
```var x = 10;
var x = undefined;
var x = ++x;
console.log(x);

NaN```
```var x = 10;
var x = ++x;
var x = x++;
console.log(x);

11```
```var x = 10;
var x = ++x;
var x = x++;
var y =x;
console.log(x);
console.log(y);

11 11```
```var x = 99;
x = x++;
console.log( x );

99```
```var x = 10;
var x = ++x;
var x = x++;
var x = x++;
var x = x++;
var y =x;
console.log(x);

11```
```var x = 10;
var x = ++x;
var x = x++;
var x = ++x;
var x = x++;
var y =x;
console.log(x, y);

12 12
```

— — -I am sure that you all will be confused on above questions and it’s output…

### Let’s explain it in a simple way.

You probably learned that x++ is the same as x = x+1. Well, that’s not the whole story. x = x++ and simple x++ both are not same.

When we do var x = x++; it simply means we are doing var x = x nothing else. you’ve just set x back to its old value: !! It is not same as var x = x + 1;
But
When we do x++ only: it is same as x = x + 1;

Example :

```var x = 10;
var x = x++;
console.log(x);

the value of x is still > 10;```
```var x = 12;
x++;
console.log(x);

// Now the value of x is 13.
```

### Another important question. what will be the output for the below code?

```var x = 0;
var loop = function(){
while(x < 3){
console.log(“I’m looping!”);
x= x++;
}
};

loop();```

Think! Think !! Think !!

— — — — — –

— — –

— –

— –

#### And the answer is it will run as an infinite loop as per the above explanation.

Read more technical blogs – https://jsmount.com

Top Interview Questions and Answer of HTML 5 Canvas

How to draw Canvas Image, Line & Circle With HTML & JavaScript

Tips to Boost Angular App Performance | Web page Speed Optimization

JavaScript Rotate 2D matrix 90 degrees clockwise | Top Interview Question

HashTable Data Structure in JavaScript with Add Delete & Search Algorithms

Trie Data Structure – Insert Search Delete & Print Program with JavaScript

Top JavaScript Commonly asked Algorithms in Interview

JavaScript String Permutation Program with nice explanation

TypeScript New & Latest Features You should know | JS Mount

Rx JS Top Operators with examples | Rx JS interview questions

JavaScript Increment & Decrement Operator.