1.2 Logical structure “sequence”
1.2.1 Sequence Examples
Example Seq1
Problem :- For the computer studies SC exams (old syllabus 7010) students were assessed on a significant piece of practical work (project) and a theory exam. The problem is a very simple one, it is just to find out the total of the 2 assessments.
Solution :-
Data Required :- (i) marks for project
(ii) marks for theory exam
Processing involved :- total = project + theory
Output Required :- total marks
Algorithm :- (only pseudocode shown; as a supplementary exercise do the flowchart)
Read marks for Project
Read marks for Theory exam
Add the marks together
Print the sum
Note :- Instead of Print we can say Output, Display or Write.
Pascal Program:-
program seq1_project;
var
project,theory,sum:real;
begin
write (‘Please key in marks for Project ‘);
read(project);
write (‘Please key in marks for Theory exam ‘);
readln (theory);
sum:=project + theory;
writeln (‘The sum is ‘,sum)
end.
Example Seq2
Problem :- In an order processing system it is required to calculate the total cost of any product, knowing the price and the quantity ordered.
Solution :-
Data Required :- (i) product code
(ii) quantity ordered
(ii) unit price
Processing involved :- total cost = quantity ordered * unit price
Output Required :- total cost
Algorithm :- (only pseudocode shown; as a supplementary exercise do the flowchart)
Read product code
Read quantity ordered
Read unit price
total cost = quantity ordered * unit price
Print the total cost
Pascal Program:-
program seq2_order;
var
product, qty : integer;
price, cost : real;
begin
write (‘please key in the product number ‘);
readln (product);
write (‘please key in the price ‘);
readln (price);
write (‘please key in quantity required ‘);
readln (qty);
cost := qty * price;
writeln (‘Product Quantity Price Cost’);
writeln (product:5, qty:10, price:11:2, cost:13:2);
end.
Example Seq3
Problem :- A payroll program is to calculate the total pay of an employee.
Solution :-
Data Required :- (i) no. of hours worked
(ii) rate of pay per hour
Processing involved :- total pay = hours * rate
Output Required :- total pay
Algorithm :- (only pseudocode shown; as a supplementary exercise do the flowchart)
Read no. of hours worked
Read rate of pay per hour
Multiply the hours worked by the hourly pay rate
Print the total pay
Pascal Program:-
program seq3_payroll;
var
hours,rate,pay:real;
begin
write (‘Please enter No. of Hours worked ‘);
read(hours);
write (‘Please enter rate of pay per hour ‘);
readln (rate);
pay:=hours * rate;
writeln (‘The total pay is ‘,pay)
end.
1.1.1 Sequence Exercises
For each of the exercises below you are required to:-
- define an appropriate algorithm using pseudocode language and,
- write the corresponding pascal program to test your algorithm.
- Suppose the government is giving additional allowance to all secondary schools so that they can put tiles in all the classrooms. As a class captain you have been asked to find out the number of titles required for your classroom.
- Assuming that last term you sat for 2 tests (one theory and one practical). The maximum marks obtainable for the theory and practical tests are 45 and 15 respectively. The problem is to find out the percentage.
- In a currency conversion program, there are 2 modules. The 1st one converts Mauritian rupees to Australian dollars and the 2nd one converts Mauritian rupees to Singapore dollars. For each of the 2 modules define the algorithm and write the corresponding pascal program.