Quiz #

To answer the quiz (and check your answers), click here or scan this code:

We reproduce below the questions, for readability.

Hierarchical file system #

On most modern computers, for a given user:

• the desktop is a directory
• the desktop is the home directory
• the desktop is a sub-directory of the home directory
• the desktop is the root of the hierarchical file system
• the home directory is the root of the hierarchical file system
• the home directory may contain hidden files
• files outside of the home directory are hidden
• every file has an absolute path
• a file may have multiple absolute paths
• two files may share an absolute path
• an absolute path can contain ..

Sets #

Which of these are sets?

If $S$ is a finite set of size $n$, then the set of all subsets of $S$ has size:

• $0$
• $n/2$
• $n$
• $n^2$
• $2^n$
• $n^n$
• infinite
• I do not know the answer

Trees #

How many nodes in this picture are the root of a tree?

• $0$
• $1$
• $2$
• $3$
• $4$
• $6$
• $10$
• infinitely many

Boolean expressions

The boolean expression

!( !( !(x = 5) & y <= 2) | z < 1)

is equivalent to:

• x != 5 & y > 2 & z >= 1
• x != 5 & y <= 2 & z >= 1
• x != 5 | y > 2 | z >= 1
• x != 5 | y <= 2 | z >= 1
• x = 5 | y <= 2 | z >= 1
• (x != 5 | y <= 2) & z >= 1
• x != 5 | (y <= 2 & z >= 1)
• (x != 5 & y <= 2) | z < 1
• (x = 5 & y <= 2) | z < 1
• x = 5 & (y <= 2 | z < 1)
• I do not know the answer

Java #

In order to be executed, a Java program must be:

• compiled
• interpreted
• either compiled or interpreted
• both compiled and interpreted
• neither compiled nor interpreted
• I do not know the answer

What does the following Java program print?

int a = 0;
int b = 1;
myMethod(a, b);
System.out.println(a);
System.out.println(b);

void myMethod(int firstInteger, int secondInteger) {
    secondInteger = firstInteger;
    firstInteger = secondInteger;
    System.out.println(firstInteger);
    System.out.println(secondInteger);
}

• a, b, 1, 0
• a, b, 0, 0
• 1, 0, a, b
• 0, 0, a, b
• 1, 0, 1, 0
• 1, 0, 0, 1
• 0, 0, 0, 1
• 0, 0, 0, 0
• 0, 1, 1, 0
• 0, 1, 0, 0

Algorithm #

Consider the following method (written in pseudocode).

boolean myMethod(int x){
  if (x == 0){
    return true
  }
  if (x < 0){
    return false
  }
  return myMethod(x - 3)
}

This method:

• is recursive
• may not terminate
• returns true iff x is a positive multiple of 3
• returns true iff x is a positive power of 3
• returns true iff x is a Fibonacci number
• returns true iff x is a multiple of the third Fibonacci number
• returns true iff x is a power of the third Fibonacci number
• returns true iff x is smaller than 2^3
• returns true iff x is smaller than 9
• returns true iff x is smaller than 3!