Memory leak concept in C++ - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to allocate memory for an integer pointer.

C++

int* ptr = new [1];

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Adouble

Bfloat

Cchar

Dint

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different type than the pointer declaration.

Forgetting to use new for dynamic allocation.

The new operator allocates memory for the specified type. Here, we want an integer pointer, so int is correct.

2fill in blank

medium

Complete the code to properly deallocate the dynamically allocated memory.

C++

delete [1];

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Aptr

Bptr[]

C*ptr

D&ptr

Attempts:

3 left

💡 Hint

Common Mistakes

Using delete[] for single object allocation.

Deleting the dereferenced pointer instead of the pointer.

To free memory allocated with new, use delete followed by the pointer variable name.

3fill in blank

hard

Fix the error in the code that causes a memory leak by missing deallocation.

C++

void leak() {
    int* data = new int[10];
    // Missing [1]
}

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Afree(data)

Bdelete data

Cdelete[] data

Ddelete *data

Attempts:

3 left

💡 Hint

Common Mistakes

Using delete instead of delete[] for arrays.

Not deleting allocated memory at all.

When memory is allocated with new[], it must be deallocated with delete[] to avoid memory leaks.

4fill in blank

hard

Fill both blanks to create a loop that allocates and then deallocates memory correctly.

C++

for (int i = 0; i < 5; i++) {
    int* ptr = new [1];
    // use ptr
    [2] ptr;
}

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Aint

Bdelete

Cdelete[]

Dfloat

Attempts:

3 left

💡 Hint

Common Mistakes

Using delete[] for single object allocation.

Forgetting to delete the allocated memory inside the loop.

Each iteration allocates an int and then deallocates it with delete to avoid memory leaks.

5fill in blank

hard

Fill all three blanks to create a dictionary-like structure using std::map that stores dynamically allocated integers and properly deletes them.

C++

#include <map>
#include <string>

void cleanup(std::map<std::string, int*>& data) {
    for (auto& [1] : data) {
        [2] [3];
    }
    data.clear();
}

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Apair

Bdelete

Cpair.second

Dauto

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect loop variable type.

Forgetting to delete the pointers before clearing the map.

The loop iterates over each pair in the map. The dynamically allocated integer is pointed to by pair.second, which must be deleted to avoid memory leaks.