"I stopped smoking" means that you were smoking, but for some reason you stopped it. For example, "I stopped smoking when my mom entered my room." Where as, "I stopped to smoke" means that you were going somewhere and stopped, so that you could smoke. For example, "I stopped to smoke on my way back home."

"I stopped smoking" usually means that I was a smoker, and stopped smoking at all -i.e. I stopped being a smoker. If it was in reference to a specific time or incident, it could also mean that I was smoking, and put the cigarette/pipe/joint/... out. "I stopped for a smoke" means that I stopped doing whatever else I was doing, and lit a smoke. As a non-smoker, I was surprised how dirty it made me feel to write that!

I love ice cream. Really love it. But it has too much fat. So I stopped EATING ice cream five years ago. (I have not eaten any ice cream for five years.) ***** I love a cup of hot cocoa. Yesterday I was working. I became tired. So I stopped TO DRINK a cup of hot cocoa and then I returned to my work. ***** Stopped + gerund = I no longer do something. (I have stopped WALKING on that street because there are lots of bad people there.) Stopped + infinitive = I stopped what I was doing. I then did something different. Then I continued with what I was doing. (The family was driving to Las Vegas from Los Angeles. They stopped TO EAT in a small town, and then they continued driving to Las Vegas.)

I stopped to smoke but realized I had stopped smoking. :P

My answer is about the same as everyone else's answer. "I stopped smoking" is when you decide to not smoke anymore. "I stopped to smoke" is when you are doing something, then you stop doing that and pull out a cigarette and light it and start smoking it. I don't smoke, so I'm so glad I don't have to go through the effort of quitting. It is very addictive and it's difficult to stop smoking. Probably the thought process of 'stopping to smoke' is difficult to stop, too. Maybe the smoker could 'stop to breathe deeply' and count to 10. I wish my father would have done that instead of 'stopping to smoke' every time he felt he needed a reason calm his thinking or something. There are probably many reasons that people smoke. One reason is simply: habit.