Arithmetic Operators
+ - * / %
Note: For 1 / operator said that if the two operands are integers still get integer (get is "business"), in order to get a float, then both operands must have a float.
2. For operator% for both operands are integers necessary (to obtain the "I" number).
Shift operators
>> right shift operator
<< the left shift operator
Right shift operator is divided into:
1. The logical shift to the right to give up, left fill 0
2. arithmetic right shift to the right to give up on the left make up the original sign bit
The left shift operator with a logical shift right;
Bitwise operator
& // bitwise (bit corresponding to binary 0, the result is 0)
| // bitwise or (corresponding to binary 1 bit, the result is 1)
^ // bitwise exclusive OR (compared with the corresponding bits of the same binary 0, 1 was different)
Note: two operand bits operator must be an integer
Specific, can be achieved by two integers exchange operator ^
a = a^b;
b = a^b;
a = a^b;
Assignment operator
= Note the difference between = and == difference
*= Example：a*=2 a = a*2
/=
+=
-=
%= a%=2 a = a%2
>>=
<<=
Unary operators
++ - + (n) - (minus) ~ * & (address) ! sizeof
Note that unary operators its priority
A difference between the front and rear ++ a ++ a: a front ++ 1 represents a first increase, and then use a ++ represents a rear first use, plus 1;
Similarly - too
sizeof operator is not a function that can be used to find the size of a number of bytes, can also be used to find a size of type
int a = 0;
sizeof(a);
sizeof( int );
sizeof can be used to find the number of array elements
Relational Operators
>=
<=
>
<
! = To test two numbers "not equal"
== tests that the two number "equal"
Be careful not to mistakenly written == when writing code =, the resulting error
Logical Operators
&& expression 1 && expression 2 expression 1 and expression 2 are true, the result was true Note: If the expression 1 is false, the expression 2 will not be calculated
|| expression 1 || 2 expression expression 1 or expression 2 is established, the results are true Note: If the expression 1 is true, the expression 2 will not be calculated
Attention on specific examples, please refer to https://blog.csdn.net/weixin_44915811/article/details/90417381
Conditions operation marks
1 expression ? Expression 2 : Expression 3 (ternary operator)
Usage rule: a calculation expression, if true, the result of the expression to 2 as a whole a result, the expression 2 is false, the result of the expression to 3 as a result of a whole
Example: a>b ? a : b
Comma expression
Expression 1, expression 2, expression 3, ...... n-expression;
Comma expression is a good plurality of expressions separated by commas, and the calculation rule is: calculated from Expression 1 to Expression n, to n as the result of the expression of the entire expression.
The subscript operator reference
[ ]
Operands: expression array name or an integer value +
int arr[10] = {0};
arr, 10 of [] of the two operands Note: [] within the variable is not only integer constant expression or plastic
Function call
( )
Operand is a function call operator: the function name and argument passing
char arr[] = "hello world";
int ret = MyStrlen (arr); for the function call operator, the function name and parameters are his operand; missing function name becomes (arr) is obviously incorrect, missing parameters MyStrlen () is not correct function itself except parameters do not need to .
Access a structure member
Structures . Member Name
Structure pointer -> member name
struct Stu
{
char name[20];
char sex[5];
};
struct Stu s;
struct Stu* ps = &s;
struct Stu s.name = "John Doe";
ps -> sex = " 男"；
