Pascal is a strongly typed, block structured programming language. The "type" of a Pascal variable consists of its semantic nature and its range of values, and can be expressed by a type name, an explicit value range, or a combination thereof. The range of values for a type is defined by the language itself for built-in types, or by the programmer for programmer defined types. Programmer-defined types are unique data types defined within the Pascal TYPE declaration section, and can consist of enumerated types, arrays, records, pointers, sets, and more, as well as combinations thereof. When variables are declared as one type, the compiler can assume that the variable will be used as that type throughout the life of the variable (whether it is global to the program, or local to a function or procedure). This consistent usage of variables makes the code easier to maintain. The compiler detects type inconsistency errors at compile time, catching many errors and reducing the need to run the code through a debugger. Additionally, it allows an optimizer to make assumptions during compilation, thereby providing more efficient executables. As John Reagan, the architect of Compaq Pascal, writes, "it was easy to write Pascal programs that would generate better code than their C equivalents" because the compiler was able to optimize based on the strict typing.
Declaring variables in Pascal is straightforward. The Pascal VAR declaration section gives the programmer the ability to declare strings, integers, real numbers and booleans (to name a few built-in types), as well as to declare variables as records or other programmer defined types. A variable defined as a RECORD allows a single variable to track several data components (or fields).
The Pascal programming language was originally developed by Niklaus Wirth, a member of the International Federation of Information Processing (IFIP) Working Group 2.1. Professor Niklaus Wirth developed Pascal to provide features that were lacking in other languages of the time. His principle objectives for Pascal were for the language to be efficent to implement and run, allow for the development of well structured and well organized programs, and to serve as a vehicle for the teaching of the important concepts of computer programming. Pascal, which was named after the mathematician Blaise Pascal, is a direct descendent from ALGOL 60, which Wirth helped develop. Pascal also draws programming components from ALGOL 68 and ALGOL-W. The original published definition for the Pascal language appeared in 1971 with latter revisons published in 1973. It was designed to teach programming techiques and topics to college students and was the language of choice to do so from the late 1960's to the late 1980's.
program HelloWorld(output);
begin
WriteLn('Hello world!')
end.
The Pascal programming language has its limits therefore we cannot use it in hardcore programming.
http:/http://groups.engin.umd.umich.edu/CIS/course.des/cis400/pascal/pascal.html
http://www.pascal-central.com/ppl/chapter2.html#Architecture
Luis Julius G. Bragais 2008-31420
Reuel Carlo P. Virtucio 2010-19846
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