& Lt; 1 & gt; very happy on the first day of blog creation! Just write a little simple, then the data type, constants and operators (C language), new operators

<1> on the first day of blog creation, I am very happy! Just write a little simple, then the data type, constants and operators (C language), new operators

[Data type]
1 --- bool

• # Include <stdbool. h> (header files specific to the bool type)
• The boolean type has only two values: 0 and 1.

2 --- char

• 1 byte, 8 bits

3 --- int occupies 4 bytes

• Short occupies 2 bytes
• Long occupies 4 bytes

4 --- float occupies 4 bytes (float type is decimal type, such as 12.34)

• Double occupies 8 bytes

5 --- default void type (to put it bluntly, it is an empty type)

[Constant]
1 ---- integer constant

• Decimal: 23
• Octal: 023
• Hexadecimal: 0x23

2 ---- floating point Constants

• Example: 12.34

3 ---- exponential constant

• 12.3e-3 => 12.3*10 ^ 3

4 ---- character constant (the character is enclosed by a pair of single quotes)

• 'A 'B' \ n' \ 0' '9'

5 ---- String constant (the string is enclosed in a pair of double quotation marks)

• "A": 'A' \ 0'
• "Hello": 'H' 'E' E' l 'l' o ''\ 0'
• The character string defaults to 0, which is '\ 0'. Therefore, the string "A" contains two characters: 'A' and' \ 0 '.

6 ---- macro definition

• # Define N 12
• Macro definition: In my understanding, it is generally to define the data -----> that is, you do not need to change the number of its values when using it.
• For example, you define an integer type array int a [N];
• Then, if you want to change its space to 64, you can define # define N 64

[Operator] (I don't think it's good to remember it by force. Remember it when you use it)

1 ---- Arithmetic Operators

• +-*/% + + --

2 ---- Relational operators

• <<=>>==! =
• The result of the relational operation is in either of the following States: 0 1

3 ---- logical operations

• &: The operation represents a false value.
• |: Or indicates true.
• ! : False or false.

The result of the logical operation is only in two states: 0 1
Short-circuit principle: When an expression can determine the result of the entire expression, the following expression does not operate.

4 ---- bitwise operation (mostly used for unsigned integer operations)

• &: Bitwise AND, false
• |: Bit or, true
• ~ : Reverse, true or false, false or true
• ^: Returns an exclusive or. The same value is 0. The difference is 1.
• >>: X> n <=> x/2 ^ n
• <: X <n <=> x * 2 ^ n

5 ---- compound Operators

• + =-= * =/= % =
• ^ = & = | = <=> =

Data exchange:

• A ^ = B;
• B ^ =;
• A ^ = B;

6 ---- conditional Operators

• <Expression 1>? <Expression 2>: <expression 3>;
• First Judge expression 1. If it is true, execute expression 2. If it is false, execute expression 3;

7 ----, (comma)

• Lowest priority

8 ---- forced type conversion

• Conversion between similar data types.

9 ---- sizeof

In fact, I personally think this is a very important function.

• For example:
• Evaluate the size of the Data opening space
• For example, you define an array int a [] = {1, 2, 3, 4, 5, 6, 7, 8}. Suppose there are many elements in the array, you need to know the size of a and you will have sizeof ();
• Or you want to know the sizeof (int) Size of an int type );