I'm new to this community and well to C++ itself. I'm trying to create a graphical
calculator which displays the parabolic path of a projectile in the form of a graph plot,
but the problem is that I don't even know how to plot points on C++.So can any one please
tell me about a command which can plot the said points in the form of a graph.
Iwill be much obliged.

C++ by itself is not built-in with such graphical tools. You need to use a library and toolkit for Graphical User Interface (GUI) programming. Depending on the environment you are working in (windows, linux, mac), there are different options. And, in general, it is difficult to use these libraries without a fair amount of knowledge in object-oriented programmin in C++.

The tool that I would recommend in Qt. You should use their IDE program (Qt Creator) and try to follow some simple tutorials (there are plenty to find by googling). But, of course, Qt, like all other GUI libraries that I know, is object-oriented, so, if you are completely new to C++, it might be hard to pick up on. For advanced plotting, you should use Qwt (add-on for Qt), but for basic drawing of points, just the QWidget/QPainter components should do just fine.