Nested loops in Javascript - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to print numbers from 1 to 2 using a loop.

Javascript

for (let i = 1; i [1] 3; i++) {
  console.log(i);
}

Drag options to blanks, or click blank then click option'

A<=

B<

C>

D>=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>=' causes the loop not to run.

Using '>' makes the loop never start.

The loop should run while i is less than 3 to print 1 and 2. Using '<' is correct.

2fill in blank

medium

Complete the inner loop to print pairs of i and j from 1 to 2.

Javascript

for (let i = 1; i <= 2; i++) {
  for (let j = 1; j [1] 3; j++) {
    console.log(i, j);
  }
}

Drag options to blanks, or click blank then click option'

A<

B<=

C>

D>=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<=' prints j = 1, 2, and 3, which is more than needed.

Using '>=' or '>' causes the loop not to run.

The inner loop should run while j is less than 3 to print pairs with j = 1 and 2.

3fill in blank

hard

Fix the error in the nested loops to print all pairs from 1 to 3.

Javascript

for (let x = 1; x <= 3; x++) {
  for (let y = 1; y [1] 3; y++) {
    console.log(x, y);
  }
}

Drag options to blanks, or click blank then click option'

A<

B>=

C<=

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' excludes the last number 3.

Using '>' or '>=' causes the loop not to run.

Using '<=' ensures y goes from 1 to 3 inclusive, printing all pairs.

4fill in blank

hard

Fill both blanks to create a nested loop that prints a 3x3 grid of stars.

Javascript

for (let row = 1; row [1] 3; row++) {
  let line = '';
  for (let col = 1; col [2] 3; col++) {
    line += '* ';
  }
  console.log(line);
}

Drag options to blanks, or click blank then click option'

A<=

B<

C>

D>=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' causes only 2 rows or columns to print.

Using '>' or '>=' causes loops not to run.

Both loops should run from 1 to 3 inclusive to print a 3x3 grid.

5fill in blank

hard

Fill all three blanks to create a nested loop that prints the multiplication table from 1 to 3.

Javascript

for (let i = 1; i [1] 3; i++) {
  for (let j = 1; j [2] 3; j++) {
    console.log(`$[3] * ${j} = ${i * j}`);
  }
}

Drag options to blanks, or click blank then click option'

A<

B<=

Ci

Dj

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' excludes the last number 3.

Using 'j' instead of 'i' in the output causes wrong multiplication.

Both loops run from 1 to 3 inclusive, and the outer loop variable i is used in the output.