Lua-分支结构

if循环

--> if
a = 50
if a < 0 then 
	print('a的值小于0')
else
	print('a的值大于0')
end
-->判断值
a = 0
if(a > 0) then
	print('a的值大于0')
	elseif a < 0 then
		print('a的值小于0')
		elseif a == 0 then
			print('a的值等于0')
		else
end	

--> 练习1： 比较两个数的大小
a = 10
b = 20
if(a > b) then
	print('a的值大于b，最大值是',a)
	elseif a < b then
	print('a的值小于b,最大值是',b)
	elseif a == b then
	print('a的值等于b')
	else
end

while循环

--> 循环 while
a = 10
while(a > 0)
	do
	print('死循环')
end

--> 练习2：输出十句 hello lua
a = 0
while(a < 10) 
	do
	print('hello lua')
	a = a + 1
end

--> 练习3：输出1 - 100 的和
a = 1
sum = 0
while a <= 100
	do
	sum = sum + a
	a = a + 1
end
print(sum)

--> 练习4：输出1-100之间所有的偶数和
a = 1
sum = 0
while a <= 100
	do
		if a % 2 == 0 then
			sum = sum + a
		end
		a = a + 1
end
print(sum)

--> 练习5：输出1-100之间的偶数和并且不超过1500，并求出最后的那个偶数值是多少
a,sum,index = 1,0,0
while a <= 100
	do
	if	a % 2 == 0 then
		sum = sum + a
		if sum > 1500 then
			index = a
			break
		end
	end
	a = a + 1
end
print('最后的那个偶数是', index - 2)
print('1-100的偶数和不超过1500的是',sum - index)

--> repeat..until(直到满足才结束)  do..while
a = 10
repeat
	print("hello world",a)
	a = a + 1
	until a > 15

--> 练习:1-100之间所有的和不超过1500
sum,number = 0,1
repeat
	sum = sum + number
	number = number + 1
	until sum > 1500
print('最后+的那个值为:',number)
print('1-100不超过1500的和为',sum - number)

for循环

--> for循环 1.数值for循环 2. 泛型for循环
--> for循环在lua中步长默认为1，可以自定义
for i=1,10 do
	print(i)
end

function f(x)
	return x^2
end

for i=1,f(5) do
	print(i)
end

--> 练习1：1-100所有和
sum = 0
for i=1,100 do
	sum = sum +i
end

--> 练习2：输出1-100所有的奇数
for i=1,100,2 do -- 这里步长设置为2，i取值就是1 3 5..
	print(i)
end