lua自带的Example（三）

--Example 21
-- repeat until statement
a = 0
repeat
    a = a+1
    print(a)
until a = 5

-----------------------Output---------------------
1
2
3
4
5


--Example 22
--for statement
--Numberic iteration form

-- Count from 1 to 4 by 1
for a = 1, 4 do io.write(a) end -- 1 ~ 4  default step=1

print()

-- Count from 1 to 6 by 3
for a =1,6,3 do io.write(a) end -- 1 ~ 6  step=3

------------------------Output----------------------
1234
14


--Example 23
--More for statement
--Swquential iteration form

for key, value in pairs({1, 2, 3, 4}) do print(key, value) end


-----------------------Output-------------------------

1     1
2     2
3     3
4     4


--Example 24
--Printing tables
--Simple Way to print tables

a = {1, 2, 3, 4, "five", "elephant", "mouse"}

for i, v in pairs(a) do print(i, v) end


-----------------------Output--------------------------
1        1
2        2
3        3
4        4
5        five
6        elephant
7        mouse


--Example 25
--break statement

a=0
while true do
    a = a+1
    if a==10 then
        break
    end
end
print(a)

-------------------------Output---------------------------

10

--Example 26
--functions
--Define a function without parameters or return value

function myFirstLuaFunction()
    print("My First Lua function was called")
end

--Call myFirstLuaFunction

myFirstLuaFunction()

--------------------------Output--------------------------
My First Lua function was called


--Example 27
--More function
--Define a function with a return value

function mySecondLuaFunction() --why??????
    return "My Second Lua function was called"
end

--Call function returning a value
a=mySecondLuaFunction("string") ----why?????
print(a)


-----------------------------Output-------------------------
My Second Lua function was called


--Example 28
--More functions
--define function with multiple parameters and multiple return values
function myFirstLuaFunctionWithMultipleReturnValue(a, b, c)
    return a, b, c,"My First Lua Function with multiple return values", 1, true

a,b,c,d,e,f = myFirstLuaFunctionWithMultipleReturnValue(1, 2, "three")
print (a,b,c,d,e,f )

------------------------------Output--------------------------
1        2        three    My First Lua Function with multiple return values
1        true


--Example 29
--Variable scoping and functions
--All variables are global in scope by default

b="global"

--To make local variable you must put the keyword 'local' in front
function myFunc()
    local b ="local variable"
    a = "global variable"
    print(a,b)
end

myfunc()
print(a,b)

--------------------------------Output--------------------------
global variable         local variable
global variable         global


--Example 30                -----Why?????
--Formatted Printing
--An implementation of printf

function printf(fmt, ..)
    io.write(string.format(fmt, ...))
end

printf("Hello %s from %s on %s\n",
        os.getenv"USER" or "there", _VERSION, os.date())


-------------------------------Output----------------------------
Hello there from Lua 5.1 on 12/30/14 20:21:35