- (____ / 4 points) Fill in the blank
a) The integer zero has a boolean value of false.
The boolean value true is
represented by the integer(s) non-zero integers.
b) What is the boolean value of this English expression:
"I got up on the right side of my bed and
pigs can fly." false.
Hint: Assume that we don't throw the pig in the air, and
that it doesn't jump off a cliff. (ie. pigs really can't
fly)
c) The while construct always executes its action at least once.
True or False: false.
d) After executing the following code, the value of p will be
2, because p=3 evaluates to true.
int p = 4;
if (p = 3) p = 2;
- (____ / 8 points) Short Answer
a) 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 |
b) What is wrong with the following code fragment?
At the second line, n is not initialized, so the value of n%2
is unpredictable.
int n;
while (n % 2) {
cout << "Please enter an even number: ";
cin >> n;
}
cout << "Thank you." << endl;
c) List four relational operators, and state what type they evaluate to:
== != <= >=
&& || < >
They ALL evaluate to the bool type.
d) Explain what the variable 's' represents when it is
printed to the screen.
Variable "s" represents the maximum integer entered by the user.
cout << "Please enter a list of integers terminated by a zero:";
int s = 0;
int n;
do {
cin >> n;
if (n > s) s = n;
} while (n);
cout << s;
- (____ / 3 points) Give the values of a, b, and c
after the execution of the following code:
a: 0, 4, 9, 18
b: 0, 4, 5, 9
c: 0, 1, 2,
Final values: a == 18, b == 9, c == 2
int a, b = 0, c;
for (a = 0 ; a <= 10 ; a += b) {
c = b % 3;
switch (c) {
case 0: b = a+4; break;
case 1: b = a+1; break;
default: b = a; break;
}
}
- (____ / 5 points)
Write a program that asks the user for a positive, odd number,
and then prints all the odd numbers from 1 to that number.
- The program should keep asking for a valid number until the user enters
one.
- To save time, don't bother commenting the code. However, you should
still indent properly and use descriptive variable names.
include <iostream.h>
void main () {
int n;
bool valid;
do {
cout << "Please enter a positive, odd number: ";
cin >> n;
valid = (n > 0 && n % 2);
if (!valid) cout << "That's not a valid number" << endl;
} while (!valid);
cout << "Odd numbers from 1 to " << n << " are:" << end;
for (int i = 0 ; i <= n ; i += 2) cout << i;
}
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