In the early days of programming- the 1950s and 1960s, when computers were slower, of limited capability and more expensive--there was a premium placed on writing programs that required as as little storage as possible and could be executed in the minimum amount of time.

Today, as hardware costs continue to fall and programmer salariescontinue to rise, the writing of programmer salaries continue to rise, the writing of programs  consumes an increasing portion of data-processing costs. In addition, as much as 80 percent of programming effort is spent on maintenance programming, that is, modifying existing programs to correct errors or to meet changing needs.

One of the early attemps at improving programmer productivity through better planning was the use of modular programming. In modular p0rogramming, the program is broken down into modules(pieces), each of which performs a single, limited function and is written and debuggedd separately from other modules. Because the purpose and size of of each module are limited, the likelihood of erros is reduced.

A collection of techniques for planning and writing of program that increases programmer productivity is Structured Programming.

Structured programming refers to a collection of techniques that have evolved from the pioneering work of Edsger Dijkstra.