how to draw a graph for equation

[Zu007]

i'm making graphical Calculator for equation.
e.g
Eq xy+y
Inputs x=-10,y=-5,y=10
and draw a graph.
how to make in c or C++ or OOP in C++

[viliml]

I suppose you mean xy+z, but I dno't know what you mean by

Inputs x=-10,y=-5,y=10

. Could you be more specific?

[Zu007]

these inputs to draw a graph.
by these inputs how to draw a graph