单项选择题

有以下程序
#include ＜iostream＞
using namespace std;
static int days []=31,28.31,30,31,30,31,31,30,31,30,31;
class date

private:
int month, day, year:
public:
date (int m, int d, int y

month = m;
day = d;
year = y;

date

void disp )

cout ＜＜year＜＜" - "＜＜month＜＜ "- "＜＜day＜＜end1;

date operator+(int day)

date dt = *this:
day += dt.day;
while day ＞ days[ dt.month - 1 ] )

day -= tays[ dt.month - 1 ];
if ( ++dt.month == 13

dt.month = 1;
dt.yeare++;


dr. day = day;
return dt;

;
int main()

date d1( 6, 20, 2004 ), d2;
d2.= d1 + 20;
d2.disp ();
return 0;

执行后的输出结果是