How to plot 2 functions with Julia - plot

Question

I am struggling to plot evaluated function and Cbebyshev approximation.
I am using Julia 1.2.0.
EDIT: Sorry, added completed code.
using Plots
pyplot()
mutable struct Cheb_struct
c::Vector{Float64}
min::Float64
max::Float64
end
function cheb_coeff(min::Float64, max::Float64, n::Int, fn::Function)::Cheb_struct
struc = Cheb_struct(Vector{Float64}(undef,n), min, max)
f = Vector{Float64}(undef,n)
p = Vector{Float64}(undef,n)
max_plus_min = (max + min) / 2
max_minus_min = (max - min) / 2
for k in 0:n-1
p[k+1] = pi * ((k+1) - 0.5) / n
f[k+1] = fn(max_plus_min + cos(p[k+1])*max_minus_min)
end
n2 = 2 / n
for j in 0:n-1
s = 0
for i in 0:n-1
s += f[i+1]*cos(j*p[i+1])
struc.c[j+1] = s * n2
end
end
return struc
end
function approximate(struc::Cheb_struct, x::Float64)::Float64
x1 = (2*x - struc.max - struc.min) / (struc.max - struc.min)
x2 = 2*x1
t = s = 0
for j in length(struc.c):-1:2
pom = s
s = x2 * s - t + struc.c[j]
t = pom
end
return (x1 * s - t + struc.c[1] / 2)
end
fn = sin
struc = cheb_coeff(0.0, 1.0, 10, fn)
println("coeff:")
for x in struc.c
#printf("% .15f\n", x)
end
println("\n x eval approx eval-approx")
for x in struc.min:0.1:struc.max
eval = fn(x)
approx = approximate(struc, x)
#printf("%11.8f %12.8f %12.8f % .3e\n", x,eval, approx, eval - approx)
display(plot(x=eval,y=approx))
end
I am getting empty plot window.
I would be very grateful if someone coould how to plot these two functions.

Answer 1

You should provide a working code as an example.
However the code below can show you how to plot:
using Plots
pyplot()
fn = sin
approxf(x) = sin(x)+rand()/10
x = 0:0.1:1
evalv = fn.(x)
approxv = approxf.(x)
p = plot(evalv,approxv)
using PyPlot
PyPlot.display_figs() #needed when running in IDE such as Atom