Limited memory resources of the storage position
1. auto
The default value --- allocated memory is readable and writable
auto int a;
2. register
register int a; constraint variables defined in the modifier register
Quick access to the definition of variables,
The compiler will try to arrange the CPU registers to a register variable, if the register is less than, or will be placed in a variable memory.
Memory (Memory) register
3. static
Static state
Scenario:
Modification of three kinds of data
(1) a function of internal variables
int fun()
{
int a ; =====>>static int a;
}
(2) a function of external variables
int a;===========>> static int a;
int fun()
{
}
Modifiers (3) Function
int fun()； =====》static int fun();
4. external
5. volatile