(填空题)下列程序的输出结果是________。#include Using namespace std;Char *str(char *s1, char *s2){ char *s=s1; while (*s) s++; *s++=' '; while (*s++=*s2++); *s++=' '; return s1;}Int main( ){ char s180]={"NanJing"}; char s280]={"is"}; char s380]={"beautiful"}; str(s1, s2); cout<