# C#運算符

• 算術運算符
• 關係運營商
• 邏輯運算符
• 按位運算符
• 賦值運算符
• 其它運算符

## 1. 算術運算符

``````using System;
namespace OperatorsAppl
{
class Program
{
static void Main(string[] args)
{
int a = 21;
int b = 10;
int c;

c = a + b;
Console.WriteLine("Line 1 - Value of c is {0}", c);
c = a - b;
Console.WriteLine("Line 2 - Value of c is {0}", c);
c = a * b;
Console.WriteLine("Line 3 - Value of c is {0}", c);
c = a / b;
Console.WriteLine("Line 4 - Value of c is {0}", c);
c = a % b;
Console.WriteLine("Line 5 - Value of c is {0}", c);
c = a++;
Console.WriteLine("Line 6 - Value of c is {0}", c);
c = a--;
Console.WriteLine("Line 7 - Value of c is {0}", c);
}
}
}``````

``````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
Line 6 - Value of c is 22
Line 7 - Value of c is 20``````

## 2. 關係運算符

``````using System;
class Program
{
static void Main(string[] args)
{
int a = 21;
int b = 10;

if (a == b)
{
Console.WriteLine("Line 1 - a is equal to b");
}
else
{
Console.WriteLine("Line 1 - a is not equal to b");
}

if (a < b)
{
Console.WriteLine("Line 2 - a is less than b");
}
else
{
Console.WriteLine("Line 2 - a is not less than b");
}

if (a > b)
{
Console.WriteLine("Line 3 - a is greater than b");
}
else
{
Console.WriteLine("Line 3 - a is not greater than b");
}
/* Lets change value of a and b */
a = 5;
b = 20;

if (a <= b)
{
Console.WriteLine("Line 4 - a is either less than or equal to  b");
}

if (b >= a)
{
Console.WriteLine("Line 5-b is either greater than or equal to 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
Line 5 - b is either greater than or equal to b``````

## 3. 邏輯運算符

``````using System;
namespace OperatorsAppl
{
class Program
{
static void Main(string[] args)
{
bool a = true;
bool b = true;

if (a && b)
{
Console.WriteLine("Line 1 - Condition is true");
}

if (a || b)
{
Console.WriteLine("Line 2 - Condition is true");
}
/* lets change the value of  a and b */
a = false;
b = true;

if (a && b)
{
Console.WriteLine("Line 3 - Condition is true");
}
else
{
Console.WriteLine("Line 3 - Condition is not true");
}

if (!(a && b))
{
Console.WriteLine("Line 4 - Condition is true");
}
}
}
}``````

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

## 4. 位運算符

``````using System;
namespace OperatorsAppl
{
class Program
{
static void Main(string[] args)
{
int a = 60;            /* 60 = 0011 1100 */
int b = 13;            /* 13 = 0000 1101 */
int c = 0;

c = a & b;             /* 12 = 0000 1100 */
Console.WriteLine("Line 1 - Value of c is {0}", c );

c = a | b;             /* 61 = 0011 1101 */
Console.WriteLine("Line 2 - Value of c is {0}", c);

c = a ^ b;             /* 49 = 0011 0001 */
Console.WriteLine("Line 3 - Value of c is {0}", c);

c = ~a;                /*-61 = 1100 0011 */
Console.WriteLine("Line 4 - Value of c is {0}", c);

c = a << 2;      /* 240 = 1111 0000 */
Console.WriteLine("Line 5 - Value of c is {0}", c);

c = a >> 2;      /* 15 = 0000 1111 */
Console.WriteLine("Line 6 - Value of c is {0}", c);
}
}
}``````

``````Line 1 - Value of c is 12
Line 2 - Value of c is 61
Line 3 - Value of c is 49
Line 4 - Value of c is -61
Line 5 - Value of c is 240
Line 6 - Value of c is 15``````

## 5. 賦值運算符

``````using System;
namespace OperatorsAppl
{
class Program
{
static void Main(string[] args)
{
int a = 21;
int c;
c = a;
Console.WriteLine("Line 1 - =  Value of c = {0}", c);

c += a;
Console.WriteLine("Line 2 - += Value of c = {0}", c);

c -= a;
Console.WriteLine("Line 3 - -=  Value of c = {0}", c);

c *= a;
Console.WriteLine("Line 4 - *=  Value of c = {0}", c);

c /= a;
Console.WriteLine("Line 5 - /=  Value of c = {0}", c);

c = 200;
c %= a;
Console.WriteLine("Line 6 - %=  Value of c = {0}", c);

c <<= 2;
Console.WriteLine("Line 7 - <<=  Value of c = {0}", c);

c >>= 2;
Console.WriteLine("Line 8 - >>=  Value of c = {0}", c);

c &= 2;
Console.WriteLine("Line 9 - &=  Value of c = {0}", c);

c ^= 2;
Console.WriteLine("Line 10 - ^=  Value of c = {0}", c);

c |= 2;
Console.WriteLine("Line 11 - |=  Value of c = {0}", c);
}
}
}``````

``````Line 1 - = Value of c = 21
Line 2 - += Value of c = 42
Line 3 - -= Value of c = 21
Line 4 - *= Value of c = 441
Line 5 - /= Value of c = 21
Line 6 - %= Value of c = 11
Line 7 - <<= Value of c = 44
Line 8 - >>= Value of c = 11
Line 9 - &= Value of c = 2
Line 10 - ^= Value of c = 0
Line 11 - |= Value of c = 2``````

## 6. 其他運算符

``````using System;
namespace OperatorsAppl
{
class Program
{
static void Main(string[] args)
{
/* example of sizeof operator */
Console.WriteLine("The size of int is {0}", sizeof(int));
Console.WriteLine("The size of short is {0}", sizeof(short));
Console.WriteLine("The size of double is {0}", sizeof(double));

/* example of ternary operator */
int a, b;
a = 10;
b = (a == 1) ? 20 : 30;
Console.WriteLine("Value of b is {0}", b);

b = (a == 10) ? 20 : 30;
Console.WriteLine("Value of b is {0}", b);
}
}
}``````

``````The size of int is 4
The size of short is 2
The size of double is 8
Value of b is 30
Value of b is 20``````

## 7. C# 中的運算符優先級

``int data= 10+ 5*5 ;``

`data`變量最後的計算值爲：`35`，因爲`*`(乘法運算符)在`+`(加法運算符)之前求值。

C語言運算符的優先級和關聯性如下：

`() [] -> . ++ - -`

`+ - ! ~ ++ - - (type)* & sizeof`

`* / %`

`+ -`

`<< >>`

`< <= > >=`

`== !=`

`&`

`^`

`/`

`&&`

`//`

`?:`

`= += -= *= /= %=>>= <<= &= ^= /=`

`,`

``````using System;
namespace OperatorsAppl
{
class Program
{
static void Main(string[] args)
{
int a = 20;
int b = 10;
int c = 15;
int d = 5;
int e;
e = (a + b) * c / d;     // ( 30 * 15 ) / 5
Console.WriteLine("Value of (a + b) * c / d is : {0}", e);

e = ((a + b) * c) / d;   // (30 * 15 ) / 5
Console.WriteLine("Value of ((a + b) * c) / d is  : {0}", e);

e = (a + b) * (c / d);   // (30) * (15/5)
Console.WriteLine("Value of (a + b) * (c / d) is  : {0}", e);

e = a + (b * c) / d;    //  20 + (150/5)
Console.WriteLine("Value of a + (b * c) / d is  : {0}", e);
``````Value of (a + b) * c / d is : 90