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JuliaByExample/src/functions.jl
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# [function](https://docs.julialang.org/en/v1/manual/functions/#man-functions-1) to calculate the volume of a sphere | |
function sphere_vol(r) | |
# julia allows [Unicode names](https://docs.julialang.org/en/v1/manual/unicode-input/#Unicode-Input-1) (in UTF-8 encoding) | |
# so either "pi" or the symbol π can be used | |
return 4/3*pi*r^3 | |
end | |
# functions can also be defined more succinctly | |
quadratic(a, sqr_term, b) = (-b + sqr_term) / 2a | |
# calculates x for 0 = a*x^2+b*x+c, [arguments types](https://docs.julialang.org/en/v1/manual/functions/#Further-Reading-1) can be defined in function definitions | |
function quadratic2(a::Float64, b::Float64, c::Float64) | |
# unlike other languages 2a is equivalent to 2*a | |
# a^2 is used instead of a**2 or pow(a,2) | |
sqr_term = sqrt(b^2-4a*c) | |
r1 = quadratic(a, sqr_term, b) | |
r2 = quadratic(a, -sqr_term, b) | |
# multiple values can be returned from a function using tuples | |
# if the [return](https://docs.julialang.org/en/v1/manual/functions/#The-return-Keyword-1) keyword is omitted, the last term is returned | |
r1, r2 | |
end | |
vol = sphere_vol(3) | |
# @printf allows number formatting but does not automatically append the \n to statements, see below | |
using Printf | |
@printf "volume = %0.3f\n" vol | |
#> volume = 113.097 | |
quad1, quad2 = quadratic2(2.0, -2.0, -12.0) | |
println("result 1: ", quad1) | |
#> result 1: 3.0 | |
println("result 2: ", quad2) | |
#> result 2: -2.0 |