4.3 Program Control Structures – the Influence of Structured Programming

4.3.1 Introductory Comments

The first real step away from undisciplined program methods was made in the late '60s by a group of academics. Their proposals, summarized as Structured Programming (SP), were typified in a 1969 article by Edsgar Dijkstra. SP is a methodology used for translating module descriptions and specifications into program source code. Its primary objective is to reduce software complexity, thereby:

• Reducing the number of mistakes made in the first place
• Reducing the time and effort taken to correct such mistakes
• Improving overall reliability, correctness, and safety

As defined by Wirth, SP "is the formulation of programs as hierarchical, nested structures of statements and objects of computation." Over the years, its original ideas were modified. Nowadays, we generally consider the basic rules of SP to be that:

• Programs are designed in...