Difference between pre-increment and post-increment

[vinoth102]

x=5, y=5
x=y++ //Ans: x=5, y=6


x=5, y=6
x=++y; //Ans: x=6, y=6

[donbock]

@vinoth102 The initial condition for your second example should be y=5.

[Sherin]

Pre-increment

Pre increment operator is used to increment variable value by 1 before assigning the value to the variable.


Syntax:

a = ++x;


Post-increment

Post increment operator is used to increment variable value by 1 after assigning the value to the variable.


Syntax:

a = x++;

[Naheedmir]

++X is the prefix increment operator; this means that the value of x is first incremented and then used in the program. X++ is a postfix increment operator; this means that the value of x is first used in the program and then incremented. --x is prefixed decrement operator, this means that the value of x is first decremented and then used in the program. X-- is a postfix decrement operator, this means that the value of x is first used in the program and then decremented.

[AjayGohil]

Hi,

Preincrement take value and then increment.Post increment first increment and then take value

you can understand easily from below example.

open browser and run following piece of code in console.

var x=5;
//out put:undefined
var pre=++x;
//output:undefined
pre
//output:6
x
//output:6
var post=x++;
//output:undefined
post
//output:6