Review questions for Prelim 2
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1. allInterval
function B = allInterval(x,a,b)
% x is a length-n vector.
% B is assigned the value of 1 (true) if every x-value is in the
% interval [a,b].
% B is assigned the value of 0 (false) if at least one of the x-values
% is not in the interval [a,b].
% Your implementation should make effective use of a while-loop.
2. TotalValue
% Refer to the Cost-Inventory application in Lecture 14.
% Complete the following function...
function T = totalValue(Inv,Cost)
% T is the total value of all the inventory in all the factories
3. Censoring text
% Refer to Lec 18 on characters and strings and implement the function
% censor WITHOUT "pre-building" the string of 'X's. That is, replace the
% censored word one character at a time.
function D = censor(str, A)
% Replace all occurrences of string str in character matrix A, regardless
% of case, with 'X's.
% A is a matrix of characters.
% str is a string. Assume that str is never split across two lines in A.
% D is A with 'X's replacing the censored string str.
%
% Example: A = ['Use MATLAB '; ...
% 'in that lab.']
%
% and str = 'lab'
%
% Then D = ['Use MATXXX '; ...
% 'in that XXX.']
4. TwoClicks
% Refer to Lecture 13 and the function RandomLinks(n).
A = RandomLinks(1000);
% Note that if A(i,j) is one, then there is a link on webpage j
% to webpage i. Write a fragment that prints "yes" if it is
% possible to go from web page #100 to webpage #200 in one or two clicks.
% Thus, if A(101,100) = 1 and A(200,101) = 1 then "yes".
5. Checking for numbers in a vector/matrix
function B = vecHasNegAndPos(x)
% x is a length-n vector and n>=2
% B is assigned the value of 1 (true) if x has at least one component
% that is strictly negative and at least one component that is
% strictly positive.
% Otherise B should be assigned the value of 0.
% Your implementation should make effective use of a while-loop.
function B = matHasNegAndPos(A)
% A is an m-by-n real array with M>=2 and n>=2
% B is assigned the value of 1 (true) if A has at least one component
% that has a strictly negative value and at least one component that has a
% strictly positive value.
% Otherise B should be assigned the value of 0.
% Your implemention should make effective use of VecHasNegAndPos
6. Reduce
function B = Reduce(A)
% A is an n-by-n array with n odd and at least 3 in value.
% B is obtained by deleting all the even-indexed rows and columns.
% Thus if
% A = [ 1 2 3 4 5 ;...
% 6 7 8 9 10 ;...
% 11 12 13 14 15 ;...
% 16 17 18 19 20 ;...
% 21 22 23 24 25 ]
% then
% B = [ 1 3 5;...
% 11 13 15;...
% 21 23 25]
7. Longest
function [len, ind] = longest(C)
% Find the longest string(s) in cell array C.
% C is an n-by-1 cell array of strings, n>=1.
% len is the length of the longest string in C.
% ind is a vector, possibly of length one, containing the index number(s)
% of the string(s) with length len
8. Questions from "Insight":
M7.1.3
P8.1.5 (Clarification: y is a row vector that is the left shift of x)
P8.1.8
P9.1.4 (do not use function `deblank`)
P9.1.7 (do not use built-in functions strfind, findstr, or find)
P9.1.9 (count lower case letters only)
P9.2.5