This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
I haven't looked at it in great detail, but usually, when I see <= as the condition in a for loop, methinks it is wrong. For example, it appears that your inner (i.e., j index for loop) when i = n-1 and j=i will access array out of bounds.
Some other points to consider:
Terminate your printf string literals with \n (new line) character
Always check scanf's return value.
Try to avoid I/O altogether (nothing wrong in hard-coding your inputs within your source when you are simply trying to learn sort algorithms).
"Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away." -- Antoine de Saint-Exupery