s1：12345678、s2：1357911，并用它们初始化类U
io
的对象obj，然后调用相关的成员函数，求并集，输出集合1、集合2和并集。
三、源程序清单
i
cludeiostreamhclassU
io
privatei
tset1le
1i
tset2le
2i
tset20le
publicU
io
i
ts1i
tl1i
ts2i
tl2
set1
ewi
tl1i
tifori0il1i
set1is1ile
1l1set2
ewi
tl2fori0il2i
set2is2ile
2l2le
0i
tfi
t
umfori
ti0ile
1i
ifset1i
umretur
1retur
0voidfu
voidshowvoidU
io
fu
fori
ti0ile
1isetle
set1ifori0ile
2iiffset2i0
fsetle
set2ivoidU
io
showcout