Objective-C 中的賦值運算子

Objective-C 語言支援以下賦值運算子：

運算子	描述	示例
=	簡單賦值運算子，將右側運算元的值賦給左側運算元	C = A + B 將 A + B 的值賦給 C
+=	加法和賦值運算子，將右側運算元加到左側運算元上，並將結果賦給左側運算元	C += A 等價於 C = C + A
-=	減法和賦值運算子，從左側運算元中減去右側運算元，並將結果賦給左側運算元	C -= A 等價於 C = C - A
*=	乘法和賦值運算子，將右側運算元乘以左側運算元，並將結果賦給左側運算元	C = A 等價於 C = C A
/=	除法和賦值運算子，將左側運算元除以右側運算元，並將結果賦給左側運算元	C /= A 等價於 C = C / A
%=	取模和賦值運算子，使用兩個運算元進行取模運算，並將結果賦給左側運算元	C %= A 等價於 C = C % A
<<=	左移和賦值運算子	C <<= 2 等價於 C = C << 2
>>=	右移和賦值運算子	C >>= 2 等價於 C = C >> 2
&=	按位與和賦值運算子	C &= 2 等價於 C = C & 2
^=	按位異或和賦值運算子	C ^= 2 等價於 C = C ^ 2
\|=	按位或和賦值運算子	C \|= 2 等價於 C = C \| 2

示例

嘗試以下示例以瞭解 Objective-C 程式語言中可用的所有賦值運算子：

線上演示

#import <Foundation/Foundation.h>

int main() {
   int a = 21;
   int c ;

   c =  a;
   NSLog(@"Line 1 - =  Operator Example, Value of c = %d\n", c );

   c +=  a;
   NSLog(@"Line 2 - += Operator Example, Value of c = %d\n", c );

   c -=  a;
   NSLog(@"Line 3 - -= Operator Example, Value of c = %d\n", c );

   c *=  a;
   NSLog(@"Line 4 - *= Operator Example, Value of c = %d\n", c );

   c /=  a;
   NSLog(@"Line 5 - /= Operator Example, Value of c = %d\n", c );

   c  = 200;
   c %=  a;
   NSLog(@"Line 6 - %= Operator Example, Value of c = %d\n", c );

   c <<=  2;
   NSLog(@"Line 7 - <<= Operator Example, Value of c = %d\n", c );

   c >>=  2;
   NSLog(@"Line 8 - >>= Operator Example, Value of c = %d\n", c );

   c &=  2;
   NSLog(@"Line 9 - &= Operator Example, Value of c = %d\n", c );

   c ^=  2;
   NSLog(@"Line 10 - ^= Operator Example, Value of c = %d\n", c );

   c |=  2;
   NSLog(@"Line 11 - |= Operator Example, Value of c = %d\n", c );

}

編譯並執行上述程式時，會產生以下結果：

2013-09-07 22:00:19.263 demo[21858] Line 1 - =  Operator Example, Value of c = 21
2013-09-07 22:00:19.263 demo[21858] Line 2 - += Operator Example, Value of c = 42
2013-09-07 22:00:19.263 demo[21858] Line 3 - -= Operator Example, Value of c = 21
2013-09-07 22:00:19.263 demo[21858] Line 4 - *= Operator Example, Value of c = 441
2013-09-07 22:00:19.263 demo[21858] Line 5 - /= Operator Example, Value of c = 21
2013-09-07 22:00:19.264 demo[21858] Line 6 - %= Operator Example, Value of c = 11
2013-09-07 22:00:19.264 demo[21858] Line 7 - <<= Operator Example, Value of c = 44
2013-09-07 22:00:19.264 demo[21858] Line 8 - >>= Operator Example, Value of c = 11
2013-09-07 22:00:19.264 demo[21858] Line 9 - &= Operator Example, Value of c = 2
2013-09-07 22:00:19.264 demo[21858] Line 10 - ^= Operator Example, Value of c = 0
2013-09-07 22:00:19.264 demo[21858] Line 11 - |= Operator Example, Value of c = 2

objective_c_operators.htm

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