Character vs string comparison in C++ - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to compare a character variable with a character literal.

C++

char ch = 'a';
if (ch == [1]) {
    std::cout << "Match" << std::endl;
}

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

A"a"

B'b'

C'a'

D"b"

Attempts:

3 left

💡 Hint

Common Mistakes

Using double quotes instead of single quotes for characters.

Characters are compared using single quotes, like 'a'. Double quotes denote strings.

2fill in blank

medium

Complete the code to compare a std::string variable with a string literal.

C++

#include <string>
std::string s = "hello";
if (s == [1]) {
    std::cout << "Equal" << std::endl;
}

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

A"hello"

B'hello'

C'world'

D"world"

Attempts:

3 left

💡 Hint

Common Mistakes

Using single quotes for string literals.

Strings are compared using double quotes, like "hello". Single quotes are for characters.

3fill in blank

hard

Fix the error in the code comparing a char and a string literal.

C++

char ch = 'x';
if (ch == [1]) {
    std::cout << "Yes" << std::endl;
}

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

A'x'

B'y'

C"y"

D"x"

Attempts:

3 left

💡 Hint

Common Mistakes

Comparing char with string literal using double quotes.

Characters must be compared with single quotes, not double quotes which denote strings.

4fill in blank

hard

Fill both blanks to create a map with string keys and char values, filtering keys starting with 'a'.

C++

#include <map>
#include <string>
#include <iostream>

std::map<std::string, char> filtered = {
    {"apple", 'a'},
    {"banana", 'b'},
    {"apricot", 'a'}
};

std::map<std::string, char> result = {
    {k, v} for auto& [k, v] : filtered if k[1] [2] 'a'
};

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

A.at(0)

B[0]

C==

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using .at(0) instead of [0].

Using != instead of == for filtering.

To check the first character of a string, use indexing with [0]. To filter keys starting with 'a', use == 'a'.

5fill in blank

hard

Fill all three blanks to create a map of uppercase keys with values greater than 10.

C++

#include <map>
#include <string>
#include <cctype>

std::map<std::string, int> data = {
    {"one", 1},
    {"two", 20},
    {"three", 30}
};

std::map<std::string, int> filtered = {
    [1]: v for (const auto& [k, v] : data) if v [2] 10
};

for (const auto& [k, v] : filtered) {
    std::cout << k << ": " << v << std::endl;
}

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

Ak

B>

Cstd::toupper(k[0]) + k.substr(1)

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using k instead of transformed key.

Using < instead of > for filtering.

To create uppercase keys, transform the first character with std::toupper and append the rest with substr. Filter values greater than 10 using >. Use the original value v in the map.