Control Structures

Abstract

The aims of this chapter are to introduce:

• selection between various courses of action as part of the problem solution

• the concepts and statements in Fortran needed to support the above. In particular

  • logical expressions

  • logical operators

  • a block of statements

  • several blocks of statements

• the IF THEN ENDIF construct

• the IF THEN ELSE IF ENDIF construct

• to introduce the CASE statement with examples

• to introduce the DO loop, in three forms with examples, in particular

  • the iterative DO loop

  • the DO WHILE form

  • the DO … IF THEN EXIT END DO or repeat until form

  • the CYCLE statement

  • the EXIT statement

Summarising: as a slow-witted human being I have a very small head and I had better learn to live with it and to respect my limitations and give them full credit, rather than try to ignore them, for the latter vain effort will be punished by failure.

Edsger W. Dijkstra, Structured Programming.