This actually came up on a reality show I saw last night and it was a big deal there as the housemates tried to differentiate between Confidence and bragging. Different persons came up with different opinions which is owing to their own perspective of things. So I decided to say thing or two about it...my opinion on the topic.
Confidence is a feeling of self assurance that comes from the belief in your qualities. You know you are intelligent as a person, so you have this self assurance that you would do great when it comes to matters or things that has to do with making use of that intelligence.
Bragging on the other hand means showing off about something you don't have, in doing this you try to put yourself in a position you are not...it is mostly all talk and no action. But when you are confident about yourself, your actions speaks for you. When you brag you tend to exaggerate things than what it is.
Most a times we tend to brag to make others believe or to convince others that we are better than they are. When you don't have confidence in your abilities as a person, you would constantly try to convince those around of how good you are when in the real sense there is nothing. You quickly want to put yourself in a position where you won't be look down before someone does to you.
Confidence shows in a man when you look at the way he lives his life, he is assured knowing fully well that he got all it takes to make a move or execute a task and that he doesn't need to put anyone down to do that.
Sometimes, as easy as it sounds I still get confused about the differences in some terms because there is always a thin line between them. Although, given the explanation above I am not yet satisfied...so I'd like to hear from you all and I am tagging some persons too so I can know their opinion, 
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