merge

 int a[]={1,2,3,4,5,9,0,0,0,0,0};
  vector<int>v1(a,a+11);
  int b[]={6,7,8};
  vector<int>v2(b,b+3);
  int len=6+3;
  int k=len-1;
  int j=2;
  int i=5;


      while(j>=0&&i>=0)
      {


      if(a[i]<b[j])
        a[k--]=b[j--];
      else
        a[k--]=a[i--];

      }
   while(j>=0)
    a[k--]=b[j--];
   while(i>=0)
    a[k--]=a[i--];



  for(int i=0;i<9;i++)
    cout<<a[i];