There is a more recent offering of this course. This is an archive of the
course which was offered in Fall 2018.
CS1011
Class Exercises
Week 3 Class Exercises
## Exercise 1: if
Write a program that asks the user to enter a three letter word. The
program should indicate whether the letters in the word are in alphabetical
order, reverse alphabetical order, or neither. Sample interaction should
look like this:
<pre>
Enter three letters: aim
The three letters entered are in alphabetical order.
Enter three letters: toe
The three letters entered are in reverse alphabetical order.
Enter three letters: bye
The three letters entered are not in order.
</pre>
## Exercise 2: switch
Suppose you are making a game that needs to control a character on the
screen. The following key mappings should be used: <key>h</key> - left,
<key>j</key> - down, <key>k</key> - up, <key>l</key> - right. Write a program
that accepts a character and prints the appropriate direction. Sample
interaction should look like this:
<pre>
j
down
k
up
h
left
</pre>
## Exercise 3: Rewrite for loop as while loop
Rewrite the following `for` loop as a `while`
loop:
```
for(int i=1; i<10; i=i+1) {
System.out.println(i + "^2 = " + i*i);
}
```
## Exercise 4: Loops
Write a program that asks the user to enter a word. The program should
indicate whether the letters in the word are in alphabetical
order, reverse alphabetical order, or neither. Sample interaction should
look like this:
<pre>
Enter a word: abhors
The letters entered are in alphabetical order.
Enter a word: soon
The letters entered are in reverse alphabetical order.
Enter a word: typical
The letters entered are not in order.
</pre>
## Exercise 5: do while loop
Write a program that asks the user to enter something. If the user just
hits enter without entering any characters first, the program
should ask the user again (repeatedly, until the user enters something).
The program should then end. Hint: use `nextLine()`.
## Exercise 6: Loops
Ask the user to enter two integer values: height and width. Your program
should then generate a box of <key>*</key>s that is height tall and width
wide. Sample interaction may look like this:
<pre>
Please enter the height: 3
Please enter the width: 5
*****
*****
*****
</pre>
## Exercise 7: Loops
Ask the user to enter a name and print all of the letters in the name,
one per line. Include line numbers for the lines. Sample interaction may look
like this:
<pre>
Enter a name: Chris
Letters:
1. C
2. h
3. r
4. i
5. s
</pre>
## Exercise 8: Loops
Ask the user to enter as many positive integers as the user wants followed
by a non-positive integer. The program should then display the sum of all
positive values that are divisible by 3. Sample interaction may look
like this:
<pre>
Enter a bunch of positive integers followed by a non-positive integer:
1 2 3 4 5 6 7 8 9 10 11 18 0
Answer: 36
</pre>
## Exercise 9: Loops
Suppose you are making a game that needs to control a character on the
screen. The following key mappings should be used: <key>h</key> - left,
<key>j</key> - down, <key>k</key> - up, <key>l</key> - right. Write a program
that accepts a string of characters and generates a sequence of moves.
Characters other than the directional characters specified earlier should be
ignored. Sample interaction should look like this:
<pre>
jjlllk
down
down
right
right
right
up
</pre>
## Exercise 10: Loops
Rewrite the program in the previous exercise so that the output matches
the sample below.
<pre>
jjlllk
2 down
3 right
1 up
</pre>
