Structured English makes computer codes intelligible to non-programmers by using English words to describe each step in the process of running a program. The structures of a computer program are designed to tell the computer what to do in a logical, step-by-step way. Non-programmers, however, are unable to read the actual symbols and directions in the code, so people have created programming languages that use straightforward English words to express what happens as the real code is running. This structured English, often referred to as pseudo-code, does not actually program the computer, but it might be described as a flow chart listing each step taken as the computer follows the real program.
By breaking a task into a logical sequence of single steps, structured English enables the underlying organization of a computer program to be followed. Each step in the process is described on one line, using clear English words in capitals, usually in the form of commands or imperatives. A simple example of this is the IF-THEN-ELSE process, also known as a conditional process. If one condition is true, then a particular action occurs, but if another condition is true instead, a different action occurs. The entire IF-THEN-ELSE process is finished with an ENDIF, so this decision-making program is not confused with the next sequence of steps.
Many other commands, such as START, REPEAT, WRITE and DO are used to describe single steps in a computer program. These commands often are embedded inside other processes, creating several layers of actions within a single task. A programmer might START a process and create two or three IF-THEN decisions, one after the other, before using ENDIF to finish that process. A conditional process using IF-THEN or CASE is one of the most powerful constructions in a structured English program. It introduces the possibility of the computer making many very different decisions, depending on the existence of varying conditions.
The IF-THEN-ELSE conditional construct, or the CASE command which introduces a set of actions that should occur for several potential cases, introduce the concept of a decision tree into the program. Each possible starting condition or case would be a single branch on the tree, with each branch leading to further branches carrying particular sets of IF-THEN types of results. A change in one of those initial conditions could result in completely different end products on different branches of the tree. In structured English, these subordinate IF-THEN or CASE branches can be set apart by being indented under the commands for the larger process of which they are a part. This style of writing the program provides a great deal of precision while allowing the reader to see exactly where each small decision occurs within the broader context.
The idea of structured English has been the foundation of many types of computer programming languages. One of the first structured programming languages was Structured Query Language (SQL), which was created at International Business Machines Corporation (IBM) in the early 1970s. It has been followed over the years by many other languages that try to make computer programming clearer to ordinary readers. The underlying code that runs the computer continues to be written in the symbols most people are not able to read. The structured English programming languages, however, allow these people to design programs that are then internally translated into that code, so their computers will perform the tasks required of them.