CS 99

Summer 2002: HW 7 07.17

Solutions

1. Tracing
n = 57;
x = 0;
y = 1;
while n ~= 0
if mod( n, 2 ) ~= 0
n = floor(n/3);
else
n = n + 1;
x = x*9;
y = y + 10;
end
end

n:	57			19	6	7			2	3			1	0
x:		0					0				0
y:			1					11				21

Write your answers in the table supplied (or a reasonable facsimile) and include it with your other documents.

2. Star Patterns
In the program segments below, you may only use loops, branches, and the following types of fprintf statements:

· fprintf(‘\n’)

· fprintf(‘*’) or fprintf(‘’\\’) or fprintf(‘/’)

· fprintf(‘ ‘) % use two spaces instead of one: things won’t line up properly otherwise

A) n = input(‘Enter a positive number: ‘);
for rows = 1 : n
for cols = 1 : (n – rows + 1)
fprintf(‘*’);
end
fprintf(‘\n’);
end

B) n = input(‘Enter a positive number: ‘);
for rows = 1 : n
for cols = 1 : n
if rows == 1 | cols == 1 | cols == n | rows == n
fprintf(‘*’);
else
fprintf(‘ ‘);
end
end
fprintf(‘\n’);
end

C) n = input(‘Enter a positive number: ‘);
for rows = 1 : n
for cols = 1 : n
if rows == 1 | cols == 1 | rows == cols | cols == n | rows == n
fprintf(‘*’);
else
fprintf(‘ ‘);
end
end
fprintf(‘\n’);
end

D) n = input(‘Enter a positive number: ‘);
for rows = 1 : n
%print leading spaces
for cols = 1 : n – rows + 1
fprintf(‘ ‘);
end
%print odd number of stars
for cols = 1 : (2*rows – 1)
fprintf(‘*’);
end
fprintf(‘\n’);
end

E)* n = input(‘Enter a positive number: ‘);
for rows = 1 : 2*n
for cols = 1 : 2*n
if cols == n – row + 1 | cols == 3*n – row + 1
fprintf(‘/’);
elseif cols == n + row | col == row – n
fprintf(‘\\’);
else

fprintf(‘ ‘);
end
end
fprintf(‘\n’);
end