Page 141 - Standard Handbook Of Petroleum & Natural Gas Engineering

126 Mathematics

Constant declaration-Must precede variable declarations and be of the form
CONST
constant name = value;
constant name = value;
etc.
For example,

CONST
PI = 3.1415927;
FACT = TRUE;
PIPENUM = 27;
MINDPTH = 1500;
MAXDPTH = 7500.0;
CLRRADS = .34;

Type declaration-Must be placed after CONST sequence and before variable
declarations; used to define new (not predefined) data types either as a range
of values or as specific values within parentheses and to define arrays, records,
and files. User-defined scalar types are ordered in increasing left to right
sequence. For example,

TYPE
UNIT = (PIPE,COLLAR,MOTOR);
TEMP = ARRAY[1..34 OF REAL;
ATP = ARRAY[1..50,1..10] OF CHAR;
PREC = RECORD
TIME: REAL;
RUN: INTEGER;
CRUNIT: UNIT;
PRSSR: REAL;
END;
STACKPTR = TSTACKELEMENT;
STRING = PACKED ARRAY[ l..MAXLENGTH OF CHAR;
(* may be predefined on some systems *)
TSURF = 0.30;
CSET = SET OF 'A'..'Z';
NODE = l..PIPENUM:

Variable declaration-Placed after TYPE statements and defines the type of
each variable, array, and record used in the program unit, for example

NXTUNIT: NODE;
LOG: PREC;
COUNT INTEGER;
PTEMP: TEMP;
PREVTEMP: TEMP;
LETTER: CSET;
NAME: ARRAY[l..PO] OF CHAR;
RUNS: FILE OF PREC;
BEGIN-Introduces the executable statements in each block of statements.