Computing CS1371 for Engineers Practice Test 1
Spring 2010
Georgia Institute of Technology
College of Computing
CS1371 Computing for Engineers
Practice Test 1 Spring Semester 2010
Problem Solving
Matthew spends 25% of his 4-hour summer camp time receiving swimming instruction. If
Matthew goes to camp for 15 weeks and goes to camp only on weekdays, how many hours does
Matthew spend *NOT* receiving swimming instruction? You do not have to calculate the
answer, but rather write one or two lines of MATLAB code that will solve this for you.
Functions
1. Which one of the following statements is *false* about function headers?
A. An equal sign (=) is only required if there is output
B. Multiple inputs must be separated by commas
C. Multiple outputs must be in parenthesis and multiple inputs must be in square brackets
D. The function must have a name
E. Outputs are not required
2. Which one of the following statements is *false* about functions in MATLAB?
A. Functions must be saved in a file that is named the same as the function name.
B. Functions can access variables defined in the MATLAB workspace.
C. Functions have local scope; i.e. they have their own workspace.
D. Functions can have zero or more outputs.
E. MATLAB built-in functions can be called from functions that you write.
Coding
1. Given a variable, arr, which is an nxn array, write script that will swap the even and odd
rows.
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CS1371 Computing for Engineers Practice Test 1
Spring 2010
Coding continued
2. Given a vector, vec, write a script which counts how many perfect squares are in the vector.
Store the answer in a variable named count. A perfect square is a number whose square root is
an integer. (Hint: mod(x,1)==0 will return true if x is an integer.)
3. Write a function for the problem described below:
Function Name: strShift
Inputs (2): - a string (character array) containing a string of letters and spaces
- a scalar double containing the number of characters to shift the string by
Outputs (1) a string (character array) containing the string of letters and spaces shifted as
described by the function description.
Function Description: The function strShift takes in 2 inputs, a string containing only letters
and spaces, and a scalar double for a shift value. The function should shift only the characters
(not the spaces) by the specified shift amount. The spaces should remain in place. their This
shifted string is the only output to the function. Note: The shift value will always be > 0.
str1
str1
str2
str2
str3
str3
= strShift(Practice, 3)
=> icePract
= strShift(Hello world, 2)
=> ldHel lowor
= strShift(One Last Test Case, 1)
=> eOn eLas tTes tCas
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CS1371 Computing for Engineers Practice Test 1
Spring 2010
Tracing
1. Read the code below and answer the questions that follow:
a = [1 -2 5 6 -4 0]
a(4) = [];
a(4) = a(4) + 10;
a((a<=0)) = 100
b = a(mod(a,2)==0);
c = sum(a)/[length(a)-4];
d = a;
What are the final values of the following variables after the code above is executed in
MATLAB?
b = ____________________________________________________________________
c = ____________________________________________________________________
d = ____________________________________________________________________
2. The following commands are executed in MATLAB:
vec1
vec2
vec3
vec4
vec5
vec6
=
=
=
=
=
=
[7 8 9 2 0 8 1 2 3];
prod(vec1)
zeros(1, 4) + vec1(2:2:end)
2;
vec1~=vec4
find((vec1) == 8)
What is the final value of vec2?
A. 48384
B. 0
C. 40
D. 7
E. None of the above
What is the final value of vec3?
A. [8 9 2 0]
B. [0 0 0 0]
D. [7 9 0 1]
C. [8 2 8 2]
E. Error
What is the final value of vec5?
A. [7 8 9 0 8 1 3]
B. [0 0 0 1 0 0 0 1 0]
D. [1 1 1 0 1 1 1 0 1]
C. 0
E. None of the above
What is the final value of vec6?
A. [8 8]
B. [0 1 0 0 0 1 0 0 0]
C. [2 6]
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D. 2
E. Error
CS1371 Computing for Engineers Practice Test 1
Spring 2010
Tracing continued
function A = checkMe(P, Q, R, S)
if (P & (( Q & R) | S))
A = 1;
elseif ~P & (( Q & R ) | S)
A = 2;
elseif (~Q & P) & ( ~R )
A = 3;
elseif ~Q & (P & R)
A = 4;
else
A = 5;
end
What are the values of output in the following function calls?
output = checkMe(true, true, true, true):
__________________________________________________________________
output = checkMe(false, false, false, false):
__________________________________________________________________
output = checkMe(true, false, false, false):
__________________________________________________________________
output = checkMe(true, false, false, true):
__________________________________________________________________
output = checkMe(true, false, true, false):
__________________________________________________________________
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