Actually I practice C programs in vim editor.But font size in it is very small.Is there any option to increase the font size in vim editor?
This may not be an ideal solution but it works for me.
Just zoom in on your terminal with Ctrl+Shift++.
Zoom out with Ctrl+-
According with http://vim.wikia.com/wiki/Change_font:
That being said, if you want to change the font size in Vim editor, you have to change the font size of your terminal. To do this in gnome-terminal go to Edit → Profile Preferences:
Moreover, you can save these preferences in a new terminal profile and when you are start using Vim, use that profile.