数组归并排序

去年的一道面试题，想起来了，顺遍把代码贴到这里
两个数组合并到一起，然后排序；用set确实比较方面了

#include < iostream >
#include < set >   
#include < iterator >
#include < algorithm >   
using   namespace  std;

int  _tmain( int  argc, _TCHAR *  argv[])
{

     int  a[ 5 ] = { 2 , 5 , 1 , 2 , 3     };
     int  b[ 10 ] = { 8 , 9 , 5 , 9 , 7 , 1 , 3 , 4 , 4 , 6 };

     set < int > ist(a,a + sizeof (a) / sizeof (a[ 0 ])); 
     set < int > ::iterator  itor; 
     set < int > it(b,b + sizeof (b) / sizeof (b[ 0 ]));
     set < int > ::iterator p;
     for ( itor  =  ist.begin();itor  != ist.end(); ++ itor)   
    { 
        cout <<* itor << endl;
    }
     for (p = it.begin();p != it.end(); ++ p)
    { 
        cout <<* p << endl;

    }
    cout << " 合并后： " << endl;  

     set < int > su;
     set < int > ::iterator q;
    set_union(ist.begin(),ist.end(),it.begin(),it.end(),inserter(su,su.begin()));

     for (q = su.begin();q != su.end(); ++ q)
    {
        cout <<* q << endl;
    }
     return   0 ;
}

}