練習26：if語句

本次練習代碼

people = 20
cats = 30
dogs = 15

if people < cats :
    print "Too many cats! The world is doomed!"

if people > cats :
    print "Not many cats! The world is saved!"

if people < dogs : 
    print "The world is drooled on!"

if people > dogs :
    print "The world is dry!"

dogs += 5

if people >= dogs :
    print "people are greater than or equal to dogs."

if people <= dogs :
    print "People are less than or equal to dogs."


if people == dogs :
    print "People are dogs."

if語句

格式：

 if <布爾表達式> ：
    代碼段

if語句可以用來在語句後面創建一個代碼段，如果if中的布爾邏輯表達式爲真，則執行其中的代碼段，值得注意的是，if語句冒號後的代碼段必須進行4格縮進，否則會報錯，也就是說，if的冒號後必須有代碼段內容