For Loop Review

These questionss are designed to asssess your current understanding of for loops!

Questions 1

True or False: For loops are typically used as definitive loops.

See Answer

True!

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Question 2

Let’s write a for loop header! Say I’m writing a for loop that should loop six times. Which test(s) ensures my code will loop six times?

1.  for (int num = 1; num <= 5; num++) {
   

2.  for (int num = 1; num < 6; num = num + 1) {
   

3.  for (int num = 1; num <= 6; num++) {
   

4.  for (int num = 1; num < 7; num += 1) {
   

See Answer

Options 3 and 4 are correct! Both of these tests will cause our loop to run six times! Try going through the control flow of this for loop header for practice.

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Question 3

How many hearts will the following for loop print?

for (int hearts = 1; hearts <= 25; hearts += 1) {
    System.out.println("<3");
}

See Answer

This for loop will execute 25 times.

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Question 4

What is the output of this for loop?

Write the output in quotation marks. For example: “Hello!”

Hint

Watch out for trailing whitespace… 👀

What is trailing whitespace? Trailing whitespace is any whitespace after the last non-whitespace character in a line until the newline character, if any.

for (int counter = 0; counter <= 5; counter++) {
    System.out.print(counter + " ");
}

See Answer

The for loop runs a total of six times, each time printing out the variable counter as it’s incremented. Note there is a trailing whitespace! If you copied the output and put it in a string variable, it would look as such: String var = "0 1 2 3 4 5 ";

Question 5

[Challenge] Ho many stars ill be printed by the folloing for loop?

for (int stars = -5; stars <= 0; stars = stars + 1) {
    System.out.print("***");
}

Hint

Try following the control flow of the for loop and writing out how the value of stars changes as we progress.

See Answer

18 stars will be printed!

Note that we are starting with stars being equal to -5 and we are continuing on until stars is greater than 0!

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Question 6

[Challenge] What is the output of this for loop?

for (int loop = 10; loop >= 0; loop -= 2) {
    System.out.print(loop + " ");
}

See Answer

The output is

10 8 6 4 2 0

Note that this time our update steps subtracts 2 from the loop variable at each iteration, rather than the usual 1 we have seen so far.