Nested loops in C++ - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

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

C++

for (int i = 1; i [1] 3; i++) {
    std::cout << i << std::endl;
}

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

A>

B<=

C<

D>=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>=' causes the loop to never run.

Using '>' reverses the loop condition incorrectly.

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

2fill in blank

medium

Complete the code to print a 3x3 grid of stars using nested loops.

C++

for (int i = 0; i < 3; i++) {
    for (int j = 0; j [1] 3; j++) {
        std::cout << "*";
    }
    std::cout << std::endl;
}

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

A<

B<=

C>

D>=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<=' causes 4 stars per line.

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

The inner loop should run while j is less than 3 to print 3 stars per line.

3fill in blank

hard

Fix the error in the nested loops to print a multiplication table from 1 to 3.

C++

for (int i = 1; i <= 3; i++) {
    for (int j = 1; j [1] 3; j++) {
        std::cout << i * j << " ";
    }
    std::cout << std::endl;
}

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

A<=

B<

C>

D>=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' misses the last multiplication (when j=3).

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

Using '<=' ensures the inner loop runs for j = 1, 2, 3 to print the full table.

4fill in blank

hard

Fill both blanks to create a nested loop that prints a right triangle of stars.

C++

for (int i = 1; i [1] 5; i++) {
    for (int j = 1; j [2] i; j++) {
        std::cout << "*";
    }
    std::cout << std::endl;
}

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

A<=

B<

C>

D>=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' in the outer loop causes only 4 lines.

Using '<' in the inner loop causes one less star per line.

Both loops use '<=' to include the last value and print the correct number of stars per line.

5fill in blank

hard

Fill all three blanks to create nested loops that print a 4x4 grid with row and column numbers.

C++

for (int row = 1; row [1] 4; row++) {
    for (int col = 1; col [2] 4; col++) {
        std::cout << row [3] col << " ";
    }
    std::cout << std::endl;
}

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

A<=

B<

C*

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' causes loops to run only 3 times.

Using '*' instead of '+' changes the output meaning.

Both loops use '<=' to include 4, and '+' combines row and col numbers for output.