I'm guessing this Karbonn phone has a removable battery, because any phone with a non-removable battery should have some emergency reboot method.
Others posted about Xposed modules, I didn't notice if you said you are rooted or not, but if you are, and you install Xposed (not entirely difficult to install if you know enough to root), then checkout GravityBox, it works with lots of stock roms, and it has an option to add an Advanced Reboot menu, it even has a Screenshot option.
That is the best thing I could reccommend, if you are uncomfortable with something like that, then you really don't have any other choice but to install some kind of widget from the Play Store, I know you said not to say that, but it's just a fact, if your phone doesn't have a restart feature (which would be quite rediculous, haven't seen an Android phone like that), and you can't figure out how to use something like Xposed, then the Play Store is your only real option.
fund the codung for reboot button in status bar
but the Link You Provided is For ICS.
But still There is a Jelly bean link available but that link says do not try this on 4.0/4.2/4.3 or you will ended with SystemUI force closes (http://forum.xda-developers.com/show....php?t=2381290 )
& I have Android 4.2.1 Jelly Bean Installed(Stock OS Rooted)
May Be its better to use Xposed module or any app
Nope. 2 phones does not make a trend. I own a cell repair shop and see dozens of different phones every week. The majority offer reboot options. But save yourself the hassle, root and install an app like this: https://play.google.com/store/apps/d...ficationToggle unless you want to play with the decompiling, compiling of the app and reinstalling of an app like the systemui without having a custom recovery and a nandroid backup, which, I am trying to tell you, is a bad idea. I used to be a recognized themer back in the day and have done many mods like this. Doing this without a custom recovery is foolish unless you LIKE restoring your phone from the soft bricked state.