为啥两次*p的输出不同啊 还有参数列表里的静态变量会被怎么处理啊

#include <iostream>
using namespace std;
int* f(static int a)
{
	cout << "f中a=" << a << ' ';
	cout << &a << endl;
	return &a;
}
int main()
{
	int a = 20;
	int* p = f(a);
	cout << *p << endl;
	cout << *p << endl;
	return 0;
}