CSCI 150, Spring 2003

Given the function definition:
	function Mystery( someVal: real): real;
	begin
		if  someVal > 2.0 then
		begin
			Mystery :=  3.0 * someVal;
		end
		else
		begin
			Mystery :=  0.0;
		end;
	end;

x := Mystery(2.5);

Answer: x = 7.5

Problem 2:
Consider the procedure definition:

	procedure Demo( var number: integer; answer: real);
	begin
		number := number*2;
		answer := number + 3.5;
	end;

Suppose the caller has variables myNum and myResult whose values are 20 and 4.8 respectively. What are the values of myNum and myResult after return from the following procedure call?

Demo(myNum, myResult);

Answer: myNum = 40, myResult = 4.8

Problem 3:

a)Write a function, 
	function TenToThePower( n : integer) : integer;
that returns 10 raised to the integer power specified by n.

function TenToThePower(n : integer):integer;
var
	count : integer;
begin
	TenToThePower := 1;
	for count := 1 to n do
	begin
		TenToThePower := TenToThePower * 10;
	end;
end;

b) Write a Pascal statement to compute 10 to the power of 3 and store the answer in the variable, tenCubed.

Answer:

tenCubed := TenToThePower(3);

Problem 4: Convert to binary
237 = 11101101
45 = 00101101
63 = 00111111

Problem 5: Convert to hexadecimal
237 = ED
45 = 2D
63 = 3F

Problem 6: Convert to signed magnitude, 1's complement, and 2's complement:

Decimal	Signed magnitude	1's complement	2's complement
22	00010110	00010110	00010110
-31	10011111	11100000	11100001
-22	10010110	11101001	11101010
49	00110001	00110001	00110001

Problem 7: Add the following two binary numbers:

Binary	Decimal
01110001	113
+ 00011100	+ 28
= 10001101	= 141

Problem 8: draw a circuit that computes the truth table:

a	b	c
0	0	0
0	1	1
1	0	1
1	1	0

There are several possible solutions. The simplest uses an exclusive or (XOR) gate.

Another possible solution uses AND and OR gates and Inverters.

Problem 9: Write an expression for the output of the given circuit. Draw the truth table: