运算符

F＃运算符

运算符是一个符号，通知编译器执行特定的数学或逻辑操作。 F＃拥有丰富的内置操作符，并提供以下类型的操作符

• 算术运算符
• 比较运算符
• 布尔运算符
• 位运算符

算术运算符

下表列出了所有由F＃语言支持的算术运算符。假设变量A持有10和变量B持有20话

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

当编译和执行程序时，它会产生以下输出

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

比较运算符 下表列出了所有由F＃语言支持的比较运算符。这些二进制比较运算符可用于整数和浮点类型。这些运算符返回布尔类型的值。

假设变量A持有10和变量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"

当编译和执行程序时，将产生以下输出

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

布尔运算符

下表显示了F＃语言支持的所有布尔运算符。 假设变量A holdstrue和变量B holdfalse，则

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"

当编译和执行程序时，将产生以下输出

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

位运算符

按位运算符处理位并执行逐位操作。 &&&（按位与）的真值表，||| （按位或）和^^^（逐位异或）如下

假设A = 60; 和B = 13; 现在在二进制格式，如下

A = 0011 1100
B = 0000 1101
-----------------
一个&&& B = 0000 1100
一个||| B = 0011 1101
一个^^^ B = 0011 0001
~~~ A = 1100 0011

由F＃语言支持位运算符列于下表。假设变量A持有60和变量B持有13，那么 -

运算符的优先级

下表显示了F＃语言中运算符和其他表达式关键字的优先级顺序，从最低优先级到最高优先级。

例子

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

当编译和执行程序时，将产生以下输出

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