1) basic type: the type specifier is int, occupying 4 bytes of memory;

2) short integer: short int or short, occupying basically the same byte and value range;

3) long integer: long int or Long, accounting for 4 memories in memory;

4) Unsigned type: Unsigned.

When writing variable definitions, you should pay attention to:

1, a type descriptor can be followed by multiple variables of the same type, using variable names; Separate.

2. The last variable name must be followed by; The number ends.

3. Variables must be defined before use, usually at the beginning of the function body. If it is not defined, this variable does not exist in memory. Of course not.

Extended data

Only integer data can be preceded by signed or unsigned.

Unsigned integers can only be used to store non-negative numbers.

When the input value exceeds the value range of the defined variable, the redundant part will be counted from the smallest number. If int b=2 147483648 is input, -2 147483648 is output. Input int b=-2 147483649 and output 2 147483647.

When we want to use a type with long keywords, we can give it another name, such as typedef? Unsigned short integer USI, in this case, ave is a short integer, not unsigned short integer and USIave.

C language data type:

1, basic type: int, short, long, char, float, double.

2. Construction types: array, structure, * * union and enumeration.

3. Pointer types: char *, int *, int **, and so on.