I'm tempted to buy candy on an impulse every time I'm in the grocery store and I go through check out
Why would you want to impulse buy candy?
I love candy, why wouldn't I?
Impulse purchases may give you happiness at first but have no long-term value and are unnecessary. Try to resist the urge to impulse buy and stick to items you can afford and need.
You're right, I will resist the urge to buy all the candy in the grocery store when I dont need it , how hard can it be?
I would make some exceptions.  Allow yourself a candy bar once a week so that you can look forward to it then.  That may make others day easier to avoid temptation.