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

Practice - 5 Tasks

1fill in blank

easy

Complete the code to add two integers and print the result.

C++

#include <iostream>
int main() {
    int a = 5, b = 3;
    int sum = a [1] b;
    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 subtraction - instead of addition.

Using multiplication * or division / by mistake.

The + operator adds two numbers. Here, it adds a and b to get the sum.

2fill in blank

medium

Complete the code to compare if two numbers are equal.

C++

#include <iostream>
int main() {
    int x = 10, y = 10;
    if (x [1] y) {
        std::cout << "Equal" << std::endl;
    } else {
        std::cout << "Not equal" << 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 assignment = instead of comparison ==.

Using inequality != by mistake.

The == operator checks if two values are equal. It returns true if they are the same.

3fill in blank

hard

Fix the error in the code to multiply two numbers correctly.

C++

#include <iostream>
int main() {
    int a = 4, b = 5;
    int product = a [1] b;
    std::cout << product << 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 addition + or subtraction - instead of multiplication.

Using division / by mistake.

The * operator multiplies two numbers. Using it here calculates the product of a and b.

4fill in blank

hard

Fill both blanks to create a dictionary-like structure using a map and check if a key exists.

C++

#include <iostream>
#include <string>
#include <map>
int main() {
    std::map<std::string, int> scores;
    scores["Alice"] = 90;
    if (scores.[1]("Alice") [2] scores.end()) {
        std::cout << "Alice's score is " << scores["Alice"] << std::endl;
    }
    return 0;
}

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

Afind

B==

C!=

Dcount

Attempts:

3 left

💡 Hint

Common Mistakes

Using count method incorrectly here.

Using equality == instead of not equal !=.

The find method searches for a key in the map. If the result is not equal (!=) to end(), the key exists.

5fill in blank

hard

Fill all three blanks to create a conditional expression that checks if a number is positive, negative, or zero.

C++

#include <iostream>
#include <string>
int main() {
    int num = -5;
    std::string result = (num [1] 0) ? "Positive" : ((num [2] 0) ? "Negative" : (num [3] 0 ? "Zero" : "Error"));
    std::cout << result << std::endl;
    return 0;
}

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

A>

B<

C==

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up greater than and less than operators.

Using not equal != instead of equal == for zero check.

The first blank uses > to check if num is positive. The second uses < to check if negative. The third uses == to check if zero.