Abstract Object‐oriented programming has been applied to the development of a prototype workstation to be used in airport traffic control towers. Objective‐C was used because it supports objects, classes and inheritance, and it allows easy access to system services. A number of design practices emerged as helpful in the course of development, some of which have been reported elsewhere. The notion of a framework of co‐operating classes as a paradigm of design was especially helpful. Comparisons with the size and rate of code production of an earlier, similar workstation programmed in C indicate an advantage to object‐oriented programming.

We consider a bin-packing problem where the sizes of the bins are allowed to vary and where the goal is to maximize the number of pieces packed. This problem is NP-hard. We examine a new efficient approximation algorithm which is a hybrid of two algorithms reported earlier, First-Fit Decreasing (FFD) and Best-Two Fit (B2F). The hybrid is iterative: it attempts to pack smaller and smaller suffixes of its list of pieces until it succeeds in packing an entire suffix. During each attempt, the hybrid operates by partitioning the current list of pieces and packing one part by B2F and afterward packing the other part of its list by FFD. We prove that no instance of the problem exists where an optimal algorithm can pack more than $\tfrac{4}{3}$ the number of pieces the hybrid can pack. We also give a sequence of examples for which the ratio of the number of pieces packed optimally and by our algorithm increases asymptotically to $\frac{4}{3}$.