Department of Computer
Science
Computer Science 101: Final Exam (120 minutes)
Name: NetID:
Lab Section: Date:
No questions will be answered during this
examination. If you do not understand a
question, read it again. If you still do
not understand it, make reasonable
assumptions and write them down. (Points will be deducted if unreasonable
assumptions are made.)
DO NOT CHEAT: Cheating includes not
only copying from another person but also allowing someone to copy from
you. Anyone who copies or allows someone
to copy will receive a score of zero. So
be defensive and protect your work.
This examination contains 14 pages
including this page. Check that your copy is complete, and ask for a
replacement if it is not. Do all your
work on these pages. For your own protection, in case pages come apart, write your NetID at the TOP of each page
before beginning work.
The
number of points for a question is roughly proportional to the amount of time
you may need for it. Don’t spend too much time on any one question.
Do not
forget to sign the attendance list and to write your signature on the line
below:
_______________________________________________________________________
(If your exam is misplaced and you did not sign the attendance list then you
will receive a zero score for the exam.)
You may
not use any electronic devices, book, notes or other references during this
examination.
DO NOT WRITE IN THIS SPACE
|
Section |
Possible Score |
Score |
Grader |
|
1 |
20 |
|
|
|
2 |
10 |
|
|
|
3 |
20 |
|
|
|
4 |
12 |
|
|
|
5 |
28 |
|
|
|
6 |
16 |
|
|
|
7 |
20 |
|
|
|
8 |
25 |
|
|
|
9 |
12 |
|
|
|
10 |
20 |
|
|
|
11 |
16 |
|
|
|
12 |
20 |
|
|
|
13 |
20 |
|
|
|
14 |
20 |
|
|
|
15 |
20 |
|
|
|
16 |
35 |
|
|
|
17 |
21 |
|
|
|
Total |
335 |
|
|
1. You
are in your Unix home directory.
You have the following subdirectories:
subdirectory: files in it
------------- ------------
lab7 lab7.c ,
example1.c , example2.c
lab8 lab8.c ,
guess.c
lab9
lab9.c , bandit.c
a) Assuming your pwd (current directory) is your home
directory, write a single Unix
command
to copy both example1.c and example2.c from the lab7 directory
into the lab8 directory.
b) Assuming your pwd (current directory)
is your home
directory, write a single Unix
command to make
the lab9 directory your current directory.
c) Assuming that lab9 is your current directory, write a single Unix
command to move the file
guess.c (located in the lab8 directory) into the lab9 directory. Do not change the
name of the file.
d) Assuming that lab9 is your
current directory, write a single Unix command
to rename the file
named guess.c (now located in the lab9 directory) as newguess.c .
2. a)
Write a single Unix command to compile the C program in the file named myprog.c using the gcc compiler.
b) Using Unix redirection(
<), write a single Unix command to run your program (compiled successfully
in part a) above) and read input data from the file named input.dat .
3. The
following program compiles and runs without errors. Write the output of
this program.
#include <stdio.h>
void mess(int * me, int you) {
*me = *me * 2;
you = you *3;
printf("you = %i and me =
%i\n", you, *me);
}
void main(void) {
int you;
int me;
you = 5;
me = 7;
mess(&you,me); /* Note parameter order */
printf("you = %i and me = %i\n", you, me);
}
Output:
you
= __________ and me = ____________
you
= __________ and me = ____________
4.
The
following program compiles without syntax errors and runs. Write the output of the program.
Hint:
look closely at this code.
#include <stdio.h>
void main(void) {
int x = 2.5;
if (x > 3) {
printf("D ");
}
else if (x == 2.5) {
printf("E ");
}
else {
printf("F ");
}
}
Write
the output here:
_______________________________________________________________
5.
Write a
complete program that asks a user for a number between one and ten and if the
number is between one and ten (including one and ten) prints “Good” but if it's
outside that range it prints “Sorry”.
Don't forget any necessary include
statements. Assume that the user only types integers as inputs.
6.
Complete
the code for the function rolldie below
that generates a random integer between 1 and 6 inclusive:
#include <stdio.h>
#include <stdlib.h>
int rolldie(void){
/* write your
code here */
/* make sure
to declare any variables you use */
}
void main(void) {
int r;
r = rolldie();
printf("Random number: %i\n", r);
}
7.
Complete
the program to calculate and print the average of the elements in the array arr:
#include <stdio.h>
void main(void) {
int arr[10] = {5, 3, 1, 2, 4, 7, 6, 9, 8, 0};
double average;
/* declare any variables you need here */
/* sum the values of the array */
/* compute the average */
/* print the average */
}
8.
Fill in
the blanks to complete the program below.
This program reads the contents of the file input.dat into the
array named studs of data type Student .
The Student structure is defined this way:
typedef struct {
char full_name[50];
int ssn;
float tuition_due;
} Student;
The
file input.dat consists of one line
per file, in the following format:
full_name
/ ssn / tuition_due
So, for
example, the following is a line from the file:
John
Smith / 123456789 / 1234.56
void main(void) {
Student studs[10];
char filename[] = “input.dat”;
FILE *fileIn;
int count = 0;
fileIn =
fopen(______________________ , ________________);
if (fileIn == NULL){
printf(“file not found \n”);
return;
}
while(EOF != fscanf(_________________,"__________________________",
____________________________________________________________)) {
count++;
}
/* other code not show here */
}
9.
Write
the output of the following program:
#include <stdio.h>
void main(void) {
int a = 1;
switch(a) {
case 1:
printf("1 ");
case 2:
printf("2 ");
case 3:
printf("3 ");
default:
printf("d ");
}
}
Output:
_________________________________________________________
10. Write the output when the following
program executes.
int plus_one(int x) {
x = x + 1;
printf("%i ", x);
return x;
}
void plus_two(int x) {
x = x + 2;
printf("%i ", x);
return ;
}
void main(void) {
int x = 1;
x = plus_one(x);
printf("%i ", x);
plus_two(x);
printf("%i ", x);
}
Output:
__________________________________________________________
11. Given the following code fragment in C:
int x[3] = {5, 6, 7};
int * p = &x[0];
int y = p[0];
Which of the following statements produce the same output as the following statement:
printf("%i", x[0]);
Circle
all that apply:
a) printf("%i", p[0]);
b) printf("%i", y);
c) printf("%i",*p);
d) printf("%i",*x);
12. Which of the following are valid
prototypes for this function:
void myFun(int x, float y) {
/* code goes here... */
}
Circle all
correct prototypes. (Do not write any code.)
a) void
myFun(int x, float y);
b) void myFun(int,float);
c) myFun(int x, float y);
d) int myFun(int x, float y);
e) int myFun(float y, int x);
13. Given the declarations below complete the C code by filling in the blanks with the correct answers.
#include <stdio.h> typedef struct {
double real;
double imaginary;
} complex;
complex sum(complex,complex); /* prototype */
void main(void){
complex x = {1.0, 2.0};
complex y = {1.0, 2.0}; complex z;
z = sum(x,y); /* perform "complex" sum of x and y and assign to z */
/* print the real and imaginary values(fields) of z */
printf(" real(z) = %lf ", _____________________________); printf(" imag(z) = %lf \n",_____________________________);
}
/*
to add two complex numbers use the rule {real1,imaginary1} + {real2,imaginary2} = {real1 + real2, imaginary1 + imaginary2} so {1.0,2.0} + {1.0,2.0} = {2.0,4.0} */
complex sum(complex a , complex b){ /* declare c and initialize */
/* c is initialized with the sum of a and b */ complex c = {_____________________,________________________________}; return c;
}
14. Assume the data type complex has been defined as in the previous question:
typedef struct {
double real;
double imaginary;
} complex;
Further assume p is a
pointer to a complex object and that variables named value and z have
been declared and initialized as follows:
complex * p;
double value;
complex z = {3.0 , 4.0 };
p = &z;
Circle
the valid statements (statement that do not produce compiler errors):
a) value = p.real;
b) value = p->real;
c) value = (*p).real;
d) value
= (*p)->real;
e) value
= p[0].real;
15.
Write
the output the following program produces.
#include <stdio.h>#include <string.h>
void main(void)
{
char password[32] = "CS101";
printf("%s \n", password);
printf("%c \n",password[1]);
strcpy(password, "CS105");
printf("%s \n", password);
if (strcmp("CS105", "CS105") > 0)
printf("yes \n");
else
printf("no \n");
if (strstr("CS105", "CS") != NULL) printf("good \n"); else printf("bad \n");
} Output: _________________________
_________________________
_________________________ _________________________
_________________________
16.
Fill in
the blanks and write code for a comparison function named compare_weights that compares two atomic weights. This
comparison function should tell qsort to sort elements in the array named AE in descending
order by weight. Next complete the code in main (by filling in the blanks) that
will sort the elements in descending
order and print out the elements.
#include <stdio.h>
#include <stdlib.h>
typedef struct {
char name[15];
char symbol[3];
int number;
double weight;
} Element;
/* fill in the blanks */
int compare_weights( ___________________ , _____________________)
{
/*
write your code here */
}
void main(void){
int i;
Element AE[4] ={{"Hydrogen",
"H", 1, 1.00794},
{
"Beryllium", "Be", 4, 9.01218},
{"Gold",
"Au", 79, 196.96655},
{"Carbon"
,"C" ,6 ,12.0107} };
/* fill in the blanks sort the elements
in descending order */
qsort( _________________________
,____________________________ ,
__________________________ ,_________________________ );
for(i=0; i < 4;++i)
printf("%s %s %i %lf\n",
AE[i].name, AE[i].symbol, AE[i].number,
AE[i].weight);
}
17. Complete the
following program by filling in the blanks to write a program that will
dynamically allocate memory (DMA) for an array of integers of sufficient size
to read all the numbers a user will enter at the keyboard. The program will
print the smallest value typed by the user. The first number the user types
will be the size of the array. This number is not to be stored in the array.
Your code should work correctly for any values of integers the user enters.
#include
<stdio.h>
#include <stdlib.h>
void main(void) {
int i, min;
int size; /* size of
array */
int * ptr; /* name of array */
/* prompt user to enter the size of the array
*/
printf("Enter array size: ");
scanf("%i",&size);
/* use DMA to allocate memory for array of
length = size */
ptr =
_____________________________________________ ;
/* use a loop to read size number of
values */
for(i=0;i<size;++i)
scanf("%i",
______________________ );
/* find minimum value in array */
min = _____________________ ;
for(i=0;i<size;++i)
if ( _____________ < min)
min = ________________________
/* print
smallest value */
printf("%i
\n", ________________ );
/* free DMA memory before end of program */
_____________________________
}