- Boolean Type (bool)
a) (____ / 1 point) The integer 0
has a boolean value of false.
b) (____ / 1 point) The boolean value true is
represented by the integer(s) non 0 .
c) (____ / 2 points) Fill in the truth table:
(You can abreviate true as T and false as F).
| a |
b |
a && b |
a || b |
!a |
| false | false | F | F | T |
| false | true | F | T | T |
| true | false | F | T | F |
| true | true | T | T | F |
d) (____ / 2 points) Write the following sentence as a C++ expression
without using any function calls:
"The absolute value of x+1 is greater than 4."
x + 1 > 4 || x + 1 < -4 (or) x > 3 || x
< -5
- (____ / 2 points) The break; and
continue; statements only apply to certain C++ constructs. In
each box, circle Yes if the statement does apply, and No if
it does not.
| C++ Construct |
break; |
continue; |
| while loop |
Yes |
Yes |
| for loop |
Yes |
Yes |
| multiway-if statement |
No |
No |
| switch statement |
Yes |
No |
- (____ / 3 points) Tracing: Give the values of a, b, and
c
after the execution of the following code:
| Code |
Variables |
int a, b = 0, c;
for (a = 0 ; a <= 10 ; a += b) {
c = b % 3;
switch (c) {
case 0: b = a+1; break;
case 1: b = a+4; break;
default: b = a; break;
}
}
|
a: 0 , 1 , 6 , 12
b: 0 , 1 , 5 , 6
c: 0 , 1 , 2 |
- (____ / 3 points) Convert the following while loop and
multiway-if
into a for loop that uses a
switch statement.
(Hint: you should be able to eliminate the
variable j.)
| while and if |
for and switch |
int i = 2;
while (i < 8) {
int j = i % 4;
if (j == 0 || j == 1) {
cout << "Monday" << endl;
} else if (j == 2) {
cout << "Tuesday" << endl;
} else {
cout << "Wednesday" << endl;
}
i++;
}
|
for (int i = 2 ; i < 8 ; i++) {
switch (i % 4) {
case 0:
case 1:
cout << "Monday" << endl;
break;
case 2:
cout << "Tuesday" << endl;
break;
default:
cout << "Wednesday" << endl;
break; // optional
}
}
|
- (____ / 6 points) File I/O: The following program tests your
knowledge of >>, get(), and getline().
A file called hill.txt will be read a different way each of
three times. Each time the file stream is opened with the open()
function, the file is read from the the beginning.
(
 ) is the '\n' character, and
( ) is the end of file.
Fill in the program's output in the lower-right box.
| Code |
File: hill.txt |
ifstream fin;
int x,y,z; // Keep track of these variables
char s[80]; // Basically like declaring: string s;
char c;
//-------------------------------------------------
fin.open ("hill.txt");
for (x = 0 ; !fin.eof() ; x++) fin.get(c);
fin.close();
//-------------------------------------------------
fin.open ("hill.txt");
for (y = 0 ; !fin.eof() ; y++) fin.getline(s, 80);
fin.close();
//-------------------------------------------------
fin.open ("hill.txt");
for (z = 0 ; !fin.eof() ; z++) fin >> s;
fin.close();
//-------------------------------------------------
cout << " x: " << x << endl
<< " y: " << y << endl
<< " z: " << z << endl;
|
Jack and Jill
went up the hill
to fetch a pale of water.
|
| Output |
|---|
| x: 58 y: 4 z: 14 |
|