Can anyone please help me in getting this icon back in my canon 650d
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This will happen if your lens is set to manual focus (check the AF/MF switch on your lens) or in the case when the lens you're using doesn't support autofocus. A third possibility is that your lens, or the lens mount, has been damaged and is no longer communicating correctly with the camera.
Of these, the first is probably by far the most common.
To me, this looks like the manually selected focus area. I don't know your camera specifically, but my camera displays a box that can be used for choosing the focus point when in spot focus mode and focuses on whatever is in that box. If you are able to move the box using the arrows then that is likely what this is. Try pushing the AF button and make sure that you aren't on spot AF if you want it to go away.
Note that some cameras may also show a focus indicator to provide focus confirmation when using manual focus, so you should also double check you are actually in AF, not MF, and that the lens supports AF. (Any modern Canon lens will, but some third party or lenses using adapters may not.)