String handling basics in C++ - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a string variable named greeting.

C++

#include <iostream>
#include <string>

int main() {
    std::string [1] = "Hello";
    std::cout << greeting << std::endl;
    return 0;
}

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

Ahello

Bstr

Cmessage

Dgreeting

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different variable name than the one printed.

Forgetting to include header.

The variable name should be greeting to match the output line.

2fill in blank

medium

Complete the code to get the length of the string greeting.

C++

#include <iostream>
#include <string>

int main() {
    std::string greeting = "Hello";
    std::cout << greeting.[1]() << std::endl;
    return 0;
}

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

Asize

Blength

Ccount

Dlen

Attempts:

3 left

💡 Hint

Common Mistakes

Using len() which is not a C++ string method.

Using count() which does not exist for strings.

The correct method to get string length in C++ is length().

3fill in blank

hard

Fix the error in the code to concatenate two strings correctly.

C++

#include <iostream>
#include <string>

int main() {
    std::string first = "Hello, ";
    std::string second = "World!";
    std::string combined = first [1] second;
    std::cout << combined << 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 & which is for addresses or references.

Using * which is for multiplication.

In C++, strings are concatenated using the + operator.

4fill in blank

hard

Fill both blanks to create a substring from greeting starting at index 2 with length 3.

C++

#include <iostream>
#include <string>

int main() {
    std::string greeting = "Hello";
    std::string part = greeting.substr([1], [2]);
    std::cout << part << std::endl;
    return 0;
}

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

A2

B3

C1

D4

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping the start index and length.

Using incorrect indices causing wrong substring.

The substring starts at index 2 and has length 3.

5fill in blank

hard

Fill all three blanks to check if the string greeting contains the character 'e' using find method.

C++

#include <iostream>
#include <string>

int main() {
    std::string greeting = "Hello";
    if (greeting.[1]([2]) [3] std::string::npos) {
        std::cout << "Found 'e'" << std::endl;
    } else {
        std::cout << "Not found" << std::endl;
    }
    return 0;
}

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

Afind

B'e'

C!=

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using == instead of != in the condition.

Searching for a string instead of a character.

The find method returns the position or std::string::npos if not found. We check if it is not equal to npos to confirm presence.