F＃運(yùn)算符

運(yùn)算符是一個(gè)符號(hào)，通知編譯器執(zhí)行特定的數(shù)學(xué)或邏輯操作。 F＃擁有豐富的內(nèi)置操作符，并提供以下類型的操作符

• 算術(shù)運(yùn)算符
• 比較運(yùn)算符
• 布爾運(yùn)算符
• 位運(yùn)算符

算術(shù)運(yùn)算符

下表列出了所有由F＃語(yǔ)言支持的算術(shù)運(yùn)算符。假設(shè)變量A持有10和變量B持有20話 

例子

let a : int32 = 21
let b : int32 = 10

let mutable c = a + b
printfn "Line 1 - Value of c is %d" c

c <- a - b;
printfn "Line 2 - Value of c is %d" c

c <- a * b;
printfn "Line 3 - Value of c is %d" c

c <- a / b;
printfn "Line 4 - Value of c is %d" c

c <- a % b;
printfn "Line 5 - Value of c is %d" c

當(dāng)編譯和執(zhí)行程序時(shí)，它會(huì)產(chǎn)生以下輸出 

Line 1 - Value of c is 31
Line 2 - Value of c is 11
Line 3 - Value of c is 210
Line 4 - Value of c is 2
Line 5 - Value of c is 1

比較運(yùn)算符

下表列出了所有由F＃語(yǔ)言支持的比較運(yùn)算符。這些二進(jìn)制比較運(yùn)算符可用于整數(shù)和浮點(diǎn)類型。這些運(yùn)算符返回布爾類型的值。

假設(shè)變量A持有10和變量B持有20，那么 

例子

let mutable a : int32 = 21
let mutable b : int32 = 10

if (a = b) then
   printfn "Line 1 - a is equal to b"
else
   printfn "Line 1 - a is not equal to b"

if (a < b) then
   printfn "Line 2 - a is less than b"
else
   printfn "Line 2 - a is not less than b"

if (a > b) then
   printfn "Line 3 - a is greater than b"
else
   printfn "Line 3 - a is not greater than b"

(* Lets change value of a and b *)
a <- 5
b <- 20

if (a <= b) then
   printfn "Line 4 - a is either less than or equal to b"
else
   printfn "Line4 - a is a is greater than b"

Line 1 - a is not equal to b
Line 2 - a is not less than b
Line 3 - a is greater than b
Line 4 - a is either less than or equal to b

布爾運(yùn)算符

下表顯示了F＃語(yǔ)言支持的所有布爾運(yùn)算符。 假設(shè)變量A holdstrue和變量B holdfalse，則 

例子

let mutable a : bool = true;
let mutable b : bool = true;

if ( a && b ) then
   printfn "Line 1 - Condition is true"
else
   printfn "Line 1 - Condition is not true"

if ( a || b ) then
   printfn "Line 2 - Condition is true"
else
   printfn "Line 2 - Condition is not true"

(* lets change the value of a *)

a <- false
if ( a && b ) then
   printfn "Line 3 - Condition is true"
else
   printfn "Line 3 - Condition is not true"

if ( a || b ) then
   printfn "Line 4 - Condition is true"
else
   printfn "Line 4 - Condition is not true"

當(dāng)編譯和執(zhí)行程序時(shí)，將產(chǎn)生以下輸出

Line 1 - Condition is true
Line 2 - Condition is true
Line 3 - Condition is not true
Line 4 - Condition is true

位運(yùn)算符

按位運(yùn)算符處理位并執(zhí)行逐位操作。 &&&（按位與）的真值表，||| （按位或）和^^^（逐位異或）如下 

假設(shè)A = 60; 和B = 13; 現(xiàn)在在二進(jìn)制格式，如下

A = 0011 1100
B = 0000 1101
-----------------
一個(gè)&&& B = 0000 1100
一個(gè)||| B = 0011 1101
一個(gè)^^^ B = 0011 0001
~~~ A = 1100 0011

由F＃語(yǔ)言支持位運(yùn)算符列于下表。假設(shè)變量A持有60和變量B持有13，那么 -

運(yùn)算符的優(yōu)先級(jí)

下表顯示了F＃語(yǔ)言中運(yùn)算符和其他表達(dá)式關(guān)鍵字的優(yōu)先級(jí)順序，從最低優(yōu)先級(jí)到最高優(yōu)先級(jí)。

let a : int32 = 20
let b : int32 = 10
let c : int32 = 15
let d : int32 = 5

let mutable e : int32 = 0
e <- (a + b) * c / d // ( 30 * 15 ) / 5
printfn "Value of (a + b) * c / d is : %d" e

e <- ((a + b) * c) / d // (30 * 15 ) / 5
printfn "Value of ((a + b) * c) / d is : %d" e

e <- (a + b) * (c / d) // (30) * (15/5)
printfn "Value of (a + b) * (c / d) is : %d" e

e <- a + (b * c) / d // 20 + (150/5)
printfn "Value of a + (b * c) / d is : %d" e

當(dāng)編譯和執(zhí)行程序時(shí)，將產(chǎn)生以下輸出

Value of (a + b) * c / d is : 90 
Value of ((a + b) * c) / d is : 90
Value of (a + b) * (c / d) is : 90 
Value of a + (b * c) / d is : 50