{program: calc1.pas
Author: Brenda Student
Class: CSCI 150, Section 03
Date: 2/5/03
Assignment: Lab 3
Purpose: Takes in 2 numbers and an operator. Performs 
	specified arithmetic operation.}

program calc;
var
	num1: real;	{First number}
	num2: real; {Second number}
	answer: real;  {Computed answer}
	opcode:	char;   {Operation to be performed}
	continue: string; {answer to question 'Do you want to continue?'}
begin
	writeln('Do you want to perform a calculation?');
	readln(continue);
	while continue = 'yes' do
	begin
		writeln('Please enter the first number:');
		readln(num1);
		writeln('Please enter the second number:');
		readln(num2);
		writeln('Please enter the operator (+,-,* or /):');
		readln(opcode);
		if opcode = '+' then
		begin
			answer := num1 + num2;
		end
		else if opcode = '-' then
		begin	
			answer := num1 - num2;
		end
		else if opcode = '*' then
		begin
			answer := num1 * num2;
		end
		else if opcode = '/' then
		begin
			answer := num1 / num2;
		end
		else
		begin
			answer:= 0;
			writeln('That is not a valid operator.');
		end;
		writeln('The result is ', answer:10:2);
		writeln('Do you want to perform another calculation?');
		readln(continue);
	end;
	writeln('Thank you and goodbye!');
end.  {end calc program}