CH 2 INTRODUCTION TO PASCAL PROGRAMMING program Check

CH 2 – INTRODUCTION TO PASCAL PROGRAMMING program Check. Pass; var Test. Score, Exam. Score : integer; Final. Score : real; Status : string; begin write(‘Enter the Test score: ’); readln(Testscore); write(‘Enter the Examination score: ’); readln(Examscore); Finalscore : = Test. Score * 0. 3 + Examscore * 0. 7; if Finalscore >= 50 then Status : = ‘Pass’ else Status : = ‘FAIL’; writeln(Status) end. Reserved words – words having special meanings in Pascal. Standard Identifier – predefined by Pascal. User-Defined Identifier – defined by users. Test Score Test _Score Test. Score 2 testscore OK Test Score Test. Score% 2 Test. Score if NOT OK

; program Check. Pass var Test. Score Exam. Score Final. Score real Status string , : ; : =assigns values to variables : integer; : separate variables/data type identifier , separate items in a list +, -, *, / begin write readln arithmetic operators (‘Enter the Test score: ’); (Testscore); =, <>, <, >, >=, <= (‘Enter the Examination score: ’); relational operators (Examscore); Finalscore : = Test. Score * 0. 3 + Examscore * 0. 7; () enclose arguments of >= : = ‘ ’; writeln(‘The result is ’, if Finalscore 50 then Status Pass else Status FAIL end . procedures, functions . Status ‘’ ) enclose arguments of procedures, functions ; separate statements, added at the end except then, else , end until enclose characters or string

program Check. Pass; var Test. Score, Exam. Score : integer; Final. Score : real; Status: string; begin (* Get Score *) write(‘Enter the Test score: ’); readln(Testscore); write(‘Enter the Examination score: ’); readln(Examscore); (* Calculate the final Score *) Finalscore : = Test. Score * 0. 3 + Examscore * 0. 7; (* Check Status *) if Finalscore >= 50 then Status : = ‘Pass’ else Status : = ‘FAIL’; (*Display Status *) writeln(Status) end. Comments (* *) remarks – • improve readability • Ignored by computers during compilation or executed

BASIC STRUCTURE OF A PASCAL PROGRAM Area. Circle; PROGRAM HEADING CONST PI = 3. 1416; CONSTANT DECLARATION VAR R, A : real; PROCEDURE AREA; BEGIN A : = PI * R; END; VARIABLE DECLARATION PROCEDURE DECLARATION PROGRAM BODY BEGIN WRITELN(‘Enter Radius’); READLN(R); AREA; WRITELN(‘The circle area is ’, A: 0: 2); END.

BASIC STRUCTURE OF A PASCAL PROGRAM program Check. Pass; PROGRAM HEADING var VARIABLE DECLARATION Test. Score, Exam. Score : integer; Final. Score : real; Status : string; begin write(‘Enter the Test score: ’); readln(Testscore); write(‘Enter the Examination score: ’); readln(Examscore); Finalscore : = Test. Score * 0. 3 + Examscore * 0. 7; if Finalscore >= 50 then Status : = ‘Pass’ else Status : = ‘FAIL’; writeln(Status) end. PROGRAM BODY

2. 3 BASIC DATA TYPE IN PASCAL INTEGER -32728 , -32727, …. -2, -1, 0, 1, 2, ……… , 32726, 32727 REAL 123. 45 CHAR ‘E’ STRING ‘PASS’ ‘FAIL’ ‘Enter Test Score’ BOOLEAN TRUE FALSE ARRAY 32 0. 00123 -12345. 0 ‘A’ ‘ 1’, ‘ 2’ ‘%’ 21 45 -0. 00000123 ‘ □’ ………. Test. Score 54 ’ 45’ 23 ‘Our Lady’’s College’ ‘’

PROGRAM STUDENTRECORD; VAR AGE: INTEGER; HEIGHT : REAL; CONDUCT : CHAR; NAME , CLASSNO, ADDRESS : STRING; TESTS : ARRAY[1. . 6] OF INTEGER; BEGIN AGE : = 15; HEIGHT : = 5. 7; CONDUCT : = ‘B’ ; NAME : = ‘PETER CHAN’ ; CLASSNO : = ‘ 4 C’ ; ADDRESS : = ’ 4/F, 23, NATHEN ROAD, MONGKOK’ ; TESTS[1] : = 56; TESTS[2] : =78; TESTS[3] : = 45; TESTS[4] : = 67; END.

program Check. Pass; WHY ARRAY? var Test. Score 1, Test. Score 2, Test. Score 3, , Test. Score 4 : integer; Status 1, Status 2, Status 3, Status 4: string; begin readln(Testscore 1); Supposed five students in the readln(Testscore 2); class. readln(Testscore 3); readln(Testscore 4); • need to declare 5 variables to if Testscore 1 >= 50 then Status 1 : = ‘pass’ else Status 1 : = ‘fail’; if Testscore 2 >= 50 then Status 2 : = ‘pass’ else Status 2 : = ‘fail’; if Testscore 3 >= 50 then Status 3 : = ‘pass’ else Status 3 : = ‘fail’; if Testscore 4 >= 50 then Status 4 : = ‘pass’ else Status 4 : = ‘fail’; end. store their test scores! • And 5 input statements to read their scores! • And 5 IF statements to test their status!

program Check. Pass; var Test. Score: array[1. . 4] of integer; Status: array[1. . 4] of string; I : integer; begin for I : = 1 to 4 do readln(Testscore[I]) for I : = 1 to 4 do if Testscore[I]>= 50 then Status[I] : = ‘pass’ else Status[I] : = ‘fail’; end. 21 45 54 23 Test. Score fail pass Status fail

DECLARE VARIABLE OF ARRAY DATA TYPE VARIABLE NAME : array [LOWER BOUND. . UPPER BOUND ] of <element type>; Ex 1 Test. Score : array [1. . 4] of integer; 21 45 54 23 Test. Score Ex 2 Status : array [1. . 4] of string; fail pass fail Status Ex 3 5. 3 Studentheight : array [1. . 4] of real; 6. 2 5. 9 5. 1 Studentheight Ex 4 B Grade : array [1. . 4] of char; C A D Grade Ex 5 Letter. Count : array [‘A’. . ’Z’] of integer; 20 12 ……. Letter. Count 3 34

Identify errors below and state the type of errors Line No Type Of Errors : Syntax, Runtime, Logical 1 Program Final. Score; 2 Var 3 Test. Score, Exam. Score : real; 4 Final. Score: integer; 5 Status: char; 6 Begin 7 write (‘Enter the Test score: ’) 8 Readln(Testscore); 9 write (Enter the Examination score: ); 10 readln(Examscore); 11 Finalscore = Test. Score * 0. 3 + Examscore * 0. 7; 12 if Finalscore < 50 then Status = ’PASS’ 13 else; 14 Status = ‘FAIL’; 15 writeln(Statu) 16 17 End. Corrections