int = 4      # An integer

str = "Hi"   # A string

float = 1.2  # A floating-point number

bool = true  # A boolean (also false)

typeof(int)

typeof(str)

typeof(float)

x = UInt8(1)              # 8-bit wide unsigned integer
y = Int32(-1)             # 32-bit wide signed integer
z = Float32(0.2)          # single precision
α = Float16(-1.0)         # half precision
β = ComplexF64(2. + 8im)  # Complex number (composed of two Float64)

println(typeof(1 + 1.2))
println(typeof(x * y))  # x was Uint8, y was Int32

x = Float32(1.)
4x                     # No "*" needed

println(5 % 2)

5^6

2.3^6

println(4 - Float32(2))
println(8 / 3)  # Note conversion to Float64
typeof(8 / 3)

x = 6 // 3
println(typeof(x), " ", Int(x))

√2  # == sqrt(2)

"Concatenating " * "strings is done " * "using multiplication"

Int(2.0)

x = Float32(1.0)
Float64(x)

Int(2.3)

UInt8(-1)

Float64(2.0 + 1im)

string(1.2)

ceil(Int, 2.3)

round(Int32, 4.5)

x = 1.2
println("x is currently $x.")
println("two less is $(x - 2)")

# arbitrary precision
b = big"12"; println(b, " is a ", typeof(b))
f = big"-1.2"; println(f, " is a ", typeof(f))

# Or wir an explicit cast:
b = BigInt(12)
f = BigFloat(-1.2)  # Note the difference to the above result

x = 15
println(x)
x = "abc";    # x newly assigned, memory by the "15" will be freed at some point in the future

x = 3; y = 5

if x < y
    println("x is less than y")
elseif x > y
    println("x is greater than y")
else
    println("x is equal to y")
end

x = 5
while x > 3
    println("Now x is $x")
    x -= 1
end

for i in 1:5
    println("Hello from number $i")
end

accu = 0
for j ∈ 1:0.5:3  # Note the step parameter
    accu += j
end
println(accu)

true  || println("The RHS of || is only run")
false || println("if the LHS is false")

iseven(3) && println("The RHS of || is only run")
isodd(3)  && println("if the LHS is true")

x = 3
x < 5 ? "smaller than 5" : "larger or equal 5"

z = begin
    x = 5
    y = -3
    x + y
end

# Or equivalently
z = (x = 5; y = -3; x + y)

d = randn(4)

using LinearAlgebra

import Pkg; Pkg.add("LinearAlgebra")

using LinearAlgebra
Diagonal(d)