if...elif...else Statement

1. 流程圖
   
   
   
   
2. 語法

   if expression1:
   	statement(s)
   elif expression2:
   	statement(s)
   else:
   	statement(s)
   

3. 範例：輸入一個數字，判斷是否等於 100，或者小於 100，其他則是大於 100。

   [dywang@deyu zzz]$ cat if2.py 
   #!/usr/bin/env python3
   # coding: utf-8
   
   var = input("Enter a number: ")
   num = int(var)
   if num == 100:
   	print("Which is 100")
   elif num < 100:
   	print("%d is less than 100" % num)
   else:
   	print("%d is greater than 100" % num)
   

4. 執行程式，輸入 100 , 80, 200 等數字進行測試。

   [dywang@deyu zzz]$ ./if2.py 
   Enter a number: 100
   Which is 100
   [dywang@deyu zzz]$ ./if2.py 
   Enter a number: 80
   80 is less than 100
   [dywang@deyu zzz]$ ./if2.py 
   Enter a number: 200
   200 is greater than 100