Type casting in C++ - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to convert the integer 10 to a float.

C++

int a = 10;
float b = [1];
std::cout << b << std::endl;

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Astatic_cast<float>(a)

B(int)a

Cfloat(a)

Da

Attempts:

3 left

💡 Hint

Common Mistakes

Using C-style cast like (int)a which does not convert to float.

Assigning integer directly without casting.

Use static_cast<float>(a) to convert integer a to float safely in C++.

2fill in blank

medium

Complete the code to cast a double to an integer using C-style cast.

C++

double pi = 3.14159;
int x = [1];
std::cout << x << std::endl;

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Astatic_cast<int>(pi)

B(int)pi

Cint(pi)

Dpi

Attempts:

3 left

💡 Hint

Common Mistakes

Using int(pi) which is a functional-style cast instead of C-style.

Assigning double directly to int without cast.

C-style cast (int)pi converts the double pi to an integer by truncating the decimal part.

3fill in blank

hard

Fix the error in the code by correctly casting a void pointer to an int pointer.

C++

void* ptr = nullptr;
int* iptr = [1];
std::cout << iptr << std::endl;

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Areinterpret_cast<int*>(ptr)

Bstatic_cast<int*>(ptr)

C(int*)ptr

Ddynamic_cast<int*>(ptr)

Attempts:

3 left

💡 Hint

Common Mistakes

Using dynamic_cast which only works with polymorphic types.

Using C-style cast which is less safe.

Use reinterpret_cast<int*>(ptr) to convert a void* to int* safely in C++.

4fill in blank

hard

Fill both blanks to create a map from string lengths to strings, filtering only strings longer than 3 characters.

C++

std::map<int, std::string> length_map;
for (const auto& word : words) {
    if (word.[1] > 3) {
        length_map[static_cast<int>(word.[2])] = word;
    }
}

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Aword.length()

Bsize()

Clength()

Dword.size()

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect member functions or missing static_cast for int conversion.

Using word.length() inconsistently.

Use word.size() to get the length and length() to compare string length in C++.

5fill in blank

hard

Fill all three blanks to create a vector of floats from a vector of ints by casting each element.

C++

std::vector<int> nums = {1, 2, 3, 4};
std::vector<float> floats;
for (auto [1] : nums) {
    floats.push_back([2]);
}

float first = floats[[3]];

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Anum

Bstatic_cast<float>(num)

C0

Di

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong loop variable name.

Forgetting to cast inside push_back.

Using wrong index to access vector element.

Use num as the loop variable, cast it with static_cast<float>(num), and access the first element with index 0.