[F #, Basic] easy learning series (20) ─ counting loop design of the loop (b)

Visual F#

Previous article describes is for ...... to ...... grammar, today re-introduced for ...... downto ...... grammar Hello!

---

★ syntax:

   1: for ... downto ... Counting cycle - Syntax

   2: for 
  <variable> 
    = 
   <First count (open) the start value> 
     downto 
    <count final value> 
      do
    
  
   
  
  
  

   3:      
  <main loop execution recited>
  

 

 

★ Demo:

   1: // Nobel Hsieh ( http://www.dotblogs.com.tw/nobel12 )

   2: open System;;

   3:  

   4: // for ... downto ... Counting cycle - Syntax

   . 5: // for 
  <variable> 
    = 
   <First count (open) the start value> 
     downto 
    <count final value> 
      do
    
  
   
  
  
  

   6: //      
  <recited cyclic execution body>
  

   7:  

   8: let CountAddResult (initNum, finalNum) = 

   9:     let mutable tmpTotal = 0;

  10: // compared to the previous one case, the only change to the bottom of downto

  11:     for tmpI = initNum downto finalNum do  

  12:         tmpTotal <- tmpTotal - tmpI;

  13: printfn "After the last subtraction value:% d" tmpTotal ;;

  14:  

  15: CountAddResult(100,97);;

  16: System.Console.WriteLine("*");;

  17: CountAddResult(2500,2498);;

  18:  

  19: System.Console.ReadLine();;

* 11 cycles from the first line to the line 12, are counted for the body.

* Used for ... downto .. is tired reduction of the mean

 

 

★ The results showed that:

* In this case, deliberate manner to render the use of subtraction, so, it can make you feel downto the fu!

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