Radian calculator

i have to make a program to calculate sin/tan/atan in radians without using math.h

for my for loop, is this ok?

for(double x = 0; x <= 2*3.14; x += 0.2)


** this is supposed to calculate the sin/tan of a radian value from 0 to 2pi, in increments of .2

does it work for you? if so then sure its ok! looks fine to me.

It is better style to make 3.14 and 0.2 const variables, defined above. That way they are easy to change without looking through a lot of code.