循环 #

while condition
    statements
end

i = 1
while i <= 5
    println(i)
    global i += 1
end

while true
    print("Enter a number (0 to exit): ")
    n = parse(Int, readline())
    n == 0 && break
    println("You entered: $n")
end

total = 0
while total < 100
    total += rand(1:20)
    println("Total: $total")
end

for var in iterable
    statements
end

for i in 1:5
    println(i)
end

for i in 1:2:10
    println(i)
end

for i in 10:-1:1
    println(i)
end

arr = [10, 20, 30, 40, 50]

for x in arr
    println(x)
end

for (i, x) in enumerate(arr)
    println("Index $i: $x")
end

d = Dict("a" => 1, "b" => 2, "c" => 3)

for (k, v) in d
    println("$k => $v")
end

for k in keys(d)
    println(k)
end

for v in values(d)
    println(v)
end

s = "Hello"

for c in s
    println(c)
end

for (i, c) in enumerate(s)
    println("$i: $c")
end

for i in 1:3
    for j in 1:3
        println("($i, $j)")
    end
end

for i in 1:3, j in 1:3
    println("($i, $j)")
end

mat = [1 2 3; 4 5 6; 7 8 9]

for i in 1:size(mat, 1)
    for j in 1:size(mat, 2)
        println("mat[$i,$j] = $(mat[i,j])")
    end
end

for i in axes(mat, 1), j in axes(mat, 2)
    println("mat[$i,$j] = $(mat[i,j])")
end

for i in 1:9
    for j in 1:i
        print("$(j)×$(i)=$(i*j)\t")
    end
    println()
end

for i in 1:10
    i == 5 && break
    println(i)
end

for i in 1:10
    i % 2 == 0 && continue
    println(i)
end

outer: for i in 1:3
    for j in 1:3
        if i == 2 && j == 2
            break outer
        end
        println("($i, $j)")
    end
end

for x in eachindex([10, 20, 30])
    println(x)
end

for x in Iterators.repeated(5, 3)
    println(x)
end

for x in Iterators.cycle([1, 2], 3)
    println(x)
end

for (a, b) in zip([1, 2, 3], ["a", "b", "c"])
    println("$a -> $b")
end

for x in Iterators.product([1, 2], ["a", "b"])
    println(x)
end

for x in Iterators.flatten([[1, 2], [3, 4]])
    println(x)
end

for x in Iterators.filter(x -> x > 2, [1, 2, 3, 4, 5])
    println(x)
end

[x^2 for x in 1:5]
[x for x in 1:10 if x % 2 == 0]

[x * y for x in 1:3, y in 1:3]
[(x, y) for x in 1:3 for y in 1:3]

Dict(string(i) => i^2 for i in 1:5)

function fibonacci(n)
    fib = [0, 1]
    while length(fib) < n
        push!(fib, fib[end] + fib[end-1])
    end
    return fib[1:n]
end

fibonacci(10)

function is_prime(n)
    n < 2 && return false
    for i in 2:isqrt(n)
        n % i == 0 && return false
    end
    return true
end

function primes_up_to(n)
    [i for i in 2:n if is_prime(i)]
end

primes_up_to(50)

function matrix_multiply(A, B)
    rows_A, cols_A = size(A)
    rows_B, cols_B = size(B)
    
    cols_A == rows_B || error("Dimension mismatch")
    
    C = zeros(rows_A, cols_B)
    for i in 1:rows_A
        for j in 1:cols_B
            for k in 1:cols_A
                C[i, j] += A[i, k] * B[k, j]
            end
        end
    end
    return C
end

A = [1 2; 3 4]
B = [5 6; 7 8]
matrix_multiply(A, B)

function guess_number()
    target = rand(1:100)
    guesses = 0
    
    println("Guess a number between 1 and 100")
    
    while true
        print("Your guess: ")
        guess = parse(Int, readline())
        global guesses += 1
        
        if guess == target
            println("Correct! You got it in $guesses guesses")
            break
        elseif guess < target
            println("Too low, try again")
        else
            println("Too high, try again")
        end
    end
end