Why loops are needed in C++ - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to print numbers from 1 to 5 using a loop.

C++

#include <iostream>

int main() {
    for (int i = 1; i [1] 5; i++) {
        std::cout << i << std::endl;
    }
    return 0;
}

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

A<

B<=

C>

D>=

Attempts:

3 left

💡 Hint

Common Mistakes

Using < prints only 1 to 4.

Using > or >= causes the loop to never run or run incorrectly.

The loop should run while i is less than or equal to 5 to print numbers 1 through 5.

2fill in blank

medium

Complete the code to sum numbers from 1 to 10 using a loop.

C++

#include <iostream>

int main() {
    int sum = 0;
    for (int num = 1; num [1] 10; num++) {
        sum += num;
    }
    std::cout << sum << std::endl;
    return 0;
}

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

A<=

B<

C>=

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using < excludes 10 from the sum.

Using > or >= causes the loop to not run as expected.

The loop should include 10, so use <= to sum numbers from 1 to 10.

3fill in blank

hard

Fix the error in the loop condition to print numbers from 0 to 4.

C++

#include <iostream>

int main() {
    for (int i = 0; i [1] 5; i++) {
        std::cout << i << std::endl;
    }
    return 0;
}

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

A>

B<=

C>=

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using <= prints 0 to 5 instead of 0 to 4.

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

The loop should run while i is less than 5 to print 0 through 4.

4fill in blank

hard

Fill both blanks to create a loop that prints even numbers from 2 to 10.

C++

#include <iostream>

int main() {
    for (int i = [1]; i [2] 10; i += 2) {
        std::cout << i << std::endl;
    }
    return 0;
}

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

A2

B1

C<=

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Starting at 1 prints odd numbers.

Using < excludes 10 from the output.

Start at 2 and run the loop while i is less than or equal to 10 to print even numbers.

5fill in blank

hard

Fill all three blanks to create a loop that prints the squares of numbers from 1 to 5.

C++

#include <iostream>

int main() {
    for (int [1] = 1; [2] [3] 5; [1]++) {
        std::cout << [1] * [1] << std::endl;
    }
    return 0;
}

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

Ai

C<=

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names in initialization and condition causes errors.

Using < excludes 5 from the output.

Use i as the loop variable, and run the loop while i is less than or equal to 5 to print squares from 1 to 5.