CS 2073, Computer Programming with Engineering Applications
Spring 1992
Exam 1

(20)	1.	Write a program segment which will read in two integers A and B and will write out the 
larger of the two numbers (or the common value if they are equal).  (No declarations or 
comments needed.)

(20)	2.	Each of the four examples below contains a significant error.  In each case say what the 
error is and whether it is a compile-time error (produces a message at compile time), a link-
time error (produces a message at link time), a run-time error (produces a message during 
the run of the program, along with the program output), or a logic error (produces no error 
message).

		(a)   N := 0; X := 13.0/N;

		(b)  if X = 0 then Y := 1;
		   else Y := 2;

		(c)  porgrom XYZ (input, output);

		(d)  sum := 0; count := 0;
		   while not eof(infil) do
		       readln(infil,score);
		       sum := sum + score;
		       count := count + 1;
		   
		   average := sum/count;

(20)	3.	Consider the following code segment, where X, Y, and TEMP are declared integer.

			X := 3; Y := 5;
			while X < Y do
			begin
			   TEMP := X;
			   X := Y;
			   Y := TEMP
			end;
			writeln(X, Y);


		(a)  How many times will the statements inside the while loop be executed?

		(b)  What is written out ?


(20)	4.	Consider the following Pascal program, including a function definition:

			program right_triang;
			var A, B, C: real;

			function hypot (X, Y: real): real;
			begin
			   if (X < 0.0) or (Y < 0.0) then
			      hypot := 0.0
			   else
			      hypot := sqrt(sqr(X) + sqr(Y))
			end; (* hypot *)

			begin
			   A := 3.0; B := 4.0;
			   C := hypot(A, B);
			   writeln(C)
			end.

		(a)	What will be printed out?

		(b)	How have we referred to the variables A and B in the function call hypot(A, B)?  
How have we referred to the variables X and Y in the function definition?

		(c)	Describe in some detail how the numbers 3.0 and 4.0 are moved around as the 
program is executed and how C acquires a value.

		(d)	Are the parentheses around X < 0.0 and around Y < 0.0 required?

(20)	5.	Write a program segment that will read integer numbers from the terminal until a negative 
number is entered.  The program should find and print out the average of the numbers read 
in up to the negative number.  The average should be printed out using three digits to the 
right of the decimal place.  (Thus if you type in 80, 100, 90, and -1 on separate lines, your 
program should print 90.000 as the average.  No declarations or comments are needed.)