### 第14节：Objective-C 赋值运算符

=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

```#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 );

}```

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

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