print("while:")
a = 0
while(a < 3) do
	local x = a * 3 - 1
	print("x = " .. x)
	a = a + 1
end

print("\nfor:")
for i = 1, 5 do									-- 数值for循环,默认步长为1
	print("第" .. i .. "次循环")
	i = i + 1
end
print()
for i = 5, 1, -2 do								-- 数值for循环，步长为-2
	print("第" .. i .. "次循环")
	i = i + 1
end


tab = {
	key1 = "val1",
	key2 = "val2",
	"val3"
}

print("\npairs:")
for k, v in pairs(tab) do						-- 泛型for循环，pairs可迭代table中的所有key
	print("k = " .. k .. " , v = " .. v)	
end
print("\nipairs:")			
for k, v in ipairs(tab) do						-- 泛型for循环，ipairs只可迭代table中key值为整数的
	print("k = " .. k .. " , v = " .. v)
end

print("\nrepeat:")
x = 0
repeat											-- repeat...until循环，先执行后判断条件，所以至少执行一次
	print("x = " .. x)
	x = x - 1
until(x < 0)

print("\nNested loop:")							-- 嵌套循环，在一个循环里嵌套一个或多个循环语句
y = 2
while(y > 0) do
	for j = 1, 3 do
		print(y .. " * " .. j .. " = " .. j * y)
	end
	y = y - 1
end

print("\nbreak:")
for i = 0, 10 do								-- break，退出当前循环或语句
	print("i = " .. i)
	if(i == 2) then
		print("break...")
		break
	end
end