[C language] static modifies local variables

int function(int n)
{
	int i = 1;   // Local variables are not decorated 
	if (n >= 5)
		return n;
	n += i;
	i++;
	return function(n);
}
int main()
{
	printf("%d\n",function(1));
	return 0;
}

here function Function , Shaping variables i Is not decorated , So in the function function Recursion , Function i Is redefined and assigned as 1（ That's it function after , The original i Be destroyed , Create new i ）, So the final function The return value of is 5

int function(int n)
{
	static int i = 1;  // Static modification , Give Way i There's something wrong with it function Still exist after 
	if (n >= 5)
		return n;
	n += i;
	i++;
	return function(n);
}
int main()
{
	printf("%d\n",function(1));
	return 0;
}

This one below function Function , Variable i By static modification , So when a function recurses , Functional i Will not be destroyed ,i Will continue to increase , So finally function The return value of is 7 

So we can come to the conclusion that  

1. static Modify local variables Changed the life cycle of the variable
2. Let static local variables out of scope and still exist , By the end of the program , The life cycle is over .