方法定义 #

function greet(name::String)
    println("Hello, $name!")
end

function greet(name::String, title::String)
    println("Hello, $title $name!")
end

greet("Julia")
greet("Julia", "Ms.")

methods(greet)

function process(x::Int)
    "Processing integer: $x"
end

function process(x::Float64)
    "Processing float: $x"
end

function process(x::String)
    "Processing string: $x"
end

process(10)
process(10.5)
process("hello")

function add(a::Int, b::Int)
    a + b
end

add(a::Int, b::Int) = a + b

function add(a::T, b::T) where {T<:Number}
    a + b
end

add(1, 2)
add(1.0, 2.0)

function process(x)
    "Generic: $x"
end

function process(x::Int)
    "Integer: $x"
end

function process(x::Float64)
    "Float: $x"
end

process("hello")
process(10)
process(10.5)

function calculate(x)
    x
end

function calculate(x, y)
    x + y
end

function calculate(x, y, z)
    x + y + z
end

calculate(1)
calculate(1, 2)
calculate(1, 2, 3)

methods(+)
methods(sin)

m = first(methods(+))
m.file
m.line
m.sig

@which 1 + 2
@which 1.0 + 2.0
@which [1, 2] + [3, 4]

function myshow(x)
    println("Value: $x")
end

function myshow(x::Int)
    println("Integer: $x")
end

function myshow(x::Float64)
    println("Float: $(round(x, digits=2))")
end

function myshow(x::String)
    println("String: \"$x\" ($(length(x)) chars)")
end

function myshow(arr::Vector)
    println("Vector with $(length(arr)) elements: $arr")
end

myshow(42)
myshow(3.14159)
myshow("hello")
myshow([1, 2, 3])
myshow((1, 2))

function to_int(x::Int)
    x
end

function to_int(x::Float64)
    round(Int, x)
end

function to_int(x::String)
    parse(Int, x)
end

function to_int(x::Bool)
    x ? 1 : 0
end

to_int(42)
to_int(3.7)
to_int("123")
to_int(true)

function myabs(x::Real)
    x < 0 ? -x : x
end

function myabs(x::Complex)
    sqrt(real(x)^2 + imag(x)^2)
end

function myabs(x::Vector)
    sqrt(sum(x.^2))
end

myabs(-5)
myabs(3 + 4im)
myabs([3, 4])