C/C++ :: Printing Asterisk Along A Function Of Y Columns

The assignment is to plot the functions, by implementing a function having the following prototype:

void plotPoint(double y);

This function should print a single "*" symbol, in a position determined by the value of y, and then a newline. The position of the * symbol can span over 80 columns: each column should represent a delta of length 0.1 in the value of y, and the zero should be placed on the 40-th column.

For example:
• placePoint(0) should print the * symbol on the 40th column
• placePoint(0.1) should print the * symbol on the 41st column
• placePoint(1) should print the * symbol on the 50th column
• placePoint(-1) should print the * symbol on the 30th column

Here is what I have so far:

#include <iostream>
#include <cmath>
int a;
int b;
int x;
int y;
int Func1(double a, double b )/>

[Code] ....

I'm lost now as to where to go to plot. I know that depending on the option chosen I call the corresponding function to return a value for y which is just then plugged into a function to plot it on columns of y.