How to make variable-counter in pine script?

I need to create counter like that:

var count = 0
if a == b
    count := count + 1

But it doesn’t work! help please.
I know that it is stupid question but i really dont know what to do

>Solution :

It works (and exactly like you have written)

Below is a simple test for the same where i am incrementing the count wherever close==open, and also displaying the count

//@version=5
indicator('Counter Test By Rohit',overlay=true)
var count = 0
if close == open
    count := count + 1
    label.new(bar_index,high,str.tostring(count),color=color.white)