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
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