for_each example

 struct  sum  {
     int  sum;
     sum()  :  sum(0)  { }
     void  operator()(int  i)  {  sum  +=  i;  }
 };
 int  main()  {
     int  A[ ]  =  {1,2,3,1,2,3,1,2,3,1,2,1,1,2,3};
     int  N  =  15;
     sum  s  =  for_each(A,  A  +  N,  sum());
     cout  <<  s.sum  <<  endl;
 }