运算符是一个符号，它告诉编译器执行特定的数学或逻辑操作。 Objective-C语言有丰富的内置运算符并提供了以下几种类型：
算术运算符
关系运算符
逻辑运算符
位运算符
赋值运算符
其他运算符
本教程将逐个讲解算术表达式，关系逻辑，按位分配和其他运算符。

算术运算符
下表列出了所有支持Objective-C语言的算术运算符。假设变量A=10，变量B=20，则：
显示实例
运算符        描述        示例
+        Adds two operands        A + B will give 30
-        Subtracts second operand from the first        A - B will give -10
*        Multiplies both operands        A * B will give 200
/        Divides numerator by denominator        B / A will give 2
%        Modulus Operator and remainder of after an integer division        B % A will give 0
++        Increment operator increases integer value by one        A++ will give 11
--        Decrement operator decreases integer value by one        A-- will give 9 关系运算符
下表列出了所有支持Objective-C语言的关系运算符。假设变量A=10和变量B=20，则：

显示实例
运算符        描述        示例
==        Checks if the values of two operands are equal or not; if yes, then condition becomes true.        (A == B) is not true.
!=        Checks if the values of two operands are equal or not; if values are not equal, then condition becomes true.        (A != B) is true.
>        Checks if the value of left operand is greater than the value of right operand; if yes, then condition becomes true.        (A > B) is not true.
<        Checks if the value of left operand is less than the value of right operand; if yes, then condition becomes true.        (A < B) is true.
>=        Checks if the value of left operand is greater than or equal to the value of right operand; if yes, then condition becomes true.        (A >= B) is not true.
<=        Checks if the value of left operand is less than or equal to the value of right operand; if yes, then condition becomes true.        (A <= B) is true. 逻辑运算符
下表列出了所有支持Objective-C语言的逻辑运算符。假设变量A=1，变量B=0，那么：

显示实例
运算符        描述        示例
&&        Called Logical AND operator. If both the operands are non zero then condition becomes true.        (A && B) is false.
||        Called Logical OR Operator. If any of the two operands is non zero then condition becomes true.        (A || B) is true.
!        Called Logical NOT Operator. Use to reverses the logical state of its operand. If a condition is true, then Logical NOT operator will make false.        !(A && B) is true. 位运算符
位运算符位和位操作执行位。 &, |, 和 ^ 真值表如下：

p        q        p & q        p | q        p ^ q
0        0        0        0        0
0        1        0        1        1
1        1        1        1        0
1        0        0        1        1
假设，如果A=60和B=13; 现在以二进制格式将如下：

A = 0011 1100
B = 0000 1101

-----------------

A&B = 0000 1100
A|B = 0011 1101
A^B = 0011 0001
~A  = 1100 0011
下表中列出了支持Objective-C语言的位运算符。假设变量A=60和变量B=13，那么：

显示实例
运算符        描述        例子
&        Binary AND Operator copies a bit to the result if it exists in both operands.        (A & B) will give 12, which is 0000 1100
|        Binary OR Operator copies a bit if it exists in either operand.        (A | B) will give 61, which is 0011 1101
^        Binary XOR Operator copies the bit if it is set in one operand but not both.        (A ^ B) will give 49, which is 0011 0001
~        Binary Ones Complement Operator is unary and has the effect of 'flipping' bits.        (~A ) will give -61, which is 1100 0011 in 2's complement form.
<<        Binary Left Shift Operator. The left operands value is moved left by the number of bits specified by the right operand.        A << 2 will give 240, which is 1111 0000
>>        Binary Right Shift Operator. The left operands value is moved right by the number of bits specified by the right operand.        A >> 2 will give 15, which is 0000 1111

过来看看