第14节:Objective-C 赋值运算符



支持Objective-C语言的赋值运算符有以下:

运算符描述说明示例
=Simple assignment operator, Assigns values from right side operands to left side operandC = A + B will assign value of A + B into C
+=Add AND assignment operator, It adds right operand to the left operand and assigns the result to left operandC += A 等同于 C = C + A
-=Subtract AND assignment operator, It subtracts right operand from the left operand and assigns the result to left operandC -= A 等同于 C = C - A
*=Multiply AND assignment operator, It multiplies right operand with the left operand and assigns the result to left operandC *= A 等同于 C = C * A
/=Divide AND assignment operator, It divides left operand with the right operand and assigns the result to left operandC /= A 等同于 C = C / A
%=Modulus AND assignment operator, It takes modulus using two operands and assigns the result to left operandC %= 等同于 C = C % A
<<=Left shift AND assignment operatorC <<= 2 等同于 C = C << 2
>>=Right shift AND assignment operatorC >>= 2 等同于 C = C >> 2
&=Bitwise AND assignment operatorC &= 2 等同于C = C & 2
^=bitwise exclusive OR and assignment operatorC ^= 2 等同于C = C ^ 2
|=bitwise inclusive OR and assignment operatorC |= 2 等同于 C = C | 2

例子

尝试下面的例子就明白了所有在Objective-C编程语言的赋值运算符:

#import <Foundation/Foundation.h>

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

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

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

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

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

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

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

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

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

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

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

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

}

当编译和执行上述程序,它会产生以下结果:

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


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