根据下列程序的执行结果，可以断定划线部分的修饰符应为______。执行结果：
i9a football is created.
a football is created.
i=10
a football is destroyed.
a football is created.
i=20
a football is destroyed.
a football is destroyed.
源程序：
#include＜iostream.h＞
class Football
{
public:
Football( ){cout＜＜"a football is created."＜＜endl;}
～Football( ){tout＜＜"a football is destroyed."＜＜endl;}
};
void func(int i)
{
______Football f1;
Football f2;
cout＜＜"i="＜＜i＜＜endl;
}
void main( )
{
func(10);
func(20);
}