HW03

       ptr2[3*(x+x1)]=alpha*ptr1[3*(x)] + (1-alpha)*ptr2[3*(x+x1)]; 
       ptr2[3*(x+x1)+1]=alpha*ptr1[3*(x)+1] + (1-alpha)*ptr2[3*(x+x1)+1]; 
       ptr2[3*(x+x1)+2]=alpha*ptr1[3*(x)+2] + (1-alpha)*ptr2[3*(x+x1)+2];