F5 Pascal Programming Revision – 19 Feb 2002
ARITHMETIC OPERATOR
+, - , *, /
div: integer division
mod: get the remainder (integer)
sqrt, round, trunc, random, abs
e.gtrunc(53.2) div 10 = 5
trunc(53.2) mod 10 = 3
LAB 1 : Changing Coins
Ask for user input (e.g. 52.3)
$10: 5
$5: 0
$2: 1
$1: 0
50cents: 0
20cents: 1
10 cents: 1
ANSWER
program coin(input,output);
var num : real;
dollar, cent : integer;
begin
write('Enter Money to change : ');
readln(num);
dollar := trunc(num);
cent := trunc(num*10)-(dollar*10);
writeln('Change');
writeln('$10 : ', dollar div 10);
writeln('$5 : ', (dollar mod 10) div 5 );
writeln('$2 : ', ((dollar mod 10) mod 5) div 2);
writeln('$1 : ', ((dollar mod 10) mod 5) mod 2 );
writeln('50c : ', cent div 5);
writeln('20c : ', (cent mod 5) div 2);
writeln('10c : ', (cent mod 5) mod 2);
readln;
end.
LAB 2 : Calculator (using for loop)
This is a calculator capable to perform
+, -, x, /, div, mod, power
======
Enter the first number : 10.0
Enter the operation : d
Enter the second number : 2.0
------
The integer quotient of 10.0 divided by 2.0 is 5.0
ANSWER
program calculator (input, output);
var num1, num2 : real;
oper : char;
i, j : integer;
power : real;
begin
writeln('This is a calculator capable to perform');
writeln('+, -, x, /, div, mod');
writeln('======');
write('Enter the first number : ');
readln(num1);
write('Enter the operation : ');
readln(oper);
write('Enter the second number : ');
readln(num2);
writeln('------');
if oper='+' then
writeln('The sum of ', num1:1:1, ' and ', num2:1:1, ' is ', num1+num2:1:1);
if oper='-' then
writeln('The difference of ', num1:1:1, ' and ', num2:1:1, ' is ', (num1-num2):1:1);
if oper='x' then
writeln('The product of ', num1:1:1, ' and ', num2:1:1, ' is ', num1*num2:1:1);
if oper='/' then
writeln('The quotient of ', num1:1:1, ' divided by ', num2:1:1, ' is ', num1/num2:1:1);
if oper='d' then
writeln('The integer quotient of ', num1:1:1, ' divided by ', num2:1:1, ' is ', trunc(num1) div trunc(num2));
if oper='m' then
writeln('The remainder of ', num1:1:1, ' divided by ', num2:1:1, ' is ', trunc(num1) mod trunc(num2));
if oper='p' then
begin
power := num1;
j := trunc(num2);
for i := 1 to j do
power := power * num1;
writeln('num1:1:1, ' to the power of ', num2:1:0, ' is ', power:1:1);
end;
readln;
end.
CONDITIONAL STATEMENT
EXAMPLE 1
if (boolean expression) then
statement;
EXAMPLE 2
if (boolean expression) then
begin
statement X1;
statement X2;
statement X3;
end
else
statement Y;
EXAMPLE 3
if (boolean expression) then
statement X
else if (boolean expression Y) then
statement Y
else
statement Z;
PRECEDENCE OF OPERATORS
Operator /Precedence
Not / Highest* / div mod and / High
+ - or / Low
= > < >= <= > / Lowest
NOT X < 3 < ERROR
NOT (X < 3) < CORRECT
X < 3 or Y > 4 < ERROR
(X < 3) or (Y > 4) < CORRECT
LAB 3 : PASSING MARK
Ask for user input 1) which form, 2) which subject, and 3) the mark he/she got
Determine whether he/she passes the subject.
SAMPLE 1
Which FORM is the student studying? 1
Which SUBJECT is it? Maths
What is his/her score? 68
Sorry! The F.1 student has failed in the subj. Maths
SAMPLE 2
Which FORM is the student studying? 7
Which SUBJECT is it? Maths
What is his/her score? 55
Congratulation! The F.7 student has passed the subj. Maths
Form / Chinese / English / Maths1-3 / 60 / 60 / 70
4-5 / 50 / 50 / 60
6-7 / 40 / 40 / 50
ANSWER
program passmark(input, output);
var form : integer;
subj : string;
score : integer;
pass : boolean;
begin
repeat
write ('Which FORM is the student studying? ');
readln (form);
write ('Which SUBJECT is it? ');
readln (subj);
write ('What is his/her score? ');
readln (score);
if (subj='Maths') then
begin
if (form >= 1) and (form <= 3) and (score >= 70) then
pass := true
else if ((form = 4) or (form = 5)) and (score >= 60) then
pass := true
else if ((form = 6) or (form = 7)) and (score >= 50) then
pass := true
else
pass := false;
end
else if (subj = 'Chi') or (subj = 'Eng') then
begin
if (form >= 1) and (form <= 3) and (score >= 60) then
pass := true
else if ((form = 4) or (form = 5)) and (score >= 50) then
pass := true
else if (score >= 40) then
pass := true
else
pass := false;
end;
if pass then
writeln('Congratulation! The F.',form,' student has passed the subj. ', subj)
else
writeln('Sorry! The F.',form,' student has failed in the subj. ', subj);
writeln;
writeln;
until (form = 8);
readln
end.
REPEATITIVE CONTROL STATEMENT
While Loop, Repeat Loop, For Loop
j:=100;
For count := j downto -100 do
BEGIN
count := count + 1; <- unacceptable statement because changing the counter within for loop
x := x + count;
y := y + 1;
END;
LAB 4
STEP 1 : Ask user to input a integer (must be between 1 to 20)
STEP 2 : if input 1 , then output “user input a 1’
STEP 3 : determine whether the number is a prime no. or composite no.
STEP 4 : repeat the above until user input 99
Algorithm
user input a number N
If N cannot be divided by 2,3,4, … or (N-1) then N is prime
Else N is composite
ANSWER
program primeno(input, output);
var num, i : integer;
prime : boolean;
begin
repeat
repeat
write('Please enter an integer (1-20) : ');
readln(num);
if not ((num >= 1) and (num <= 20)) then
writeln('Value out of range, please re-enter!');
until ((num >= 1) and (num <= 20)) or (num=99);
if (num = 1) then
writeln('you input 1')
else if (num > 99) then
begin
prime := true;
for i:= 2 to (num-1) do
if (num mod i) > 0 then
prime := false;
if prime then
writeln (num, ' is a prime number.')
else
writeln (num, ' is a composite number.');
end;
until (num = 99);
end.
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