Test: Dynamic Allocation - 1 - Software Development MCQ

What happens if we forget to deallocate the memory allocated using new?

Which operator is used to deallocate memory allocated for a single object in C++?

What will be the output of the following code snippet?
int* ptr = new int(5);
cout << *ptr << endl;
delete ptr;
cout << *ptr << endl;

What will be the output of the following code snippet?
int* ptr = new int[3]{1, 2, 3};
cout << *ptr << endl;
delete[] ptr;
cout << *ptr << endl;

What will be the output of the following code snippet?
int a = 10;
int& ref = a;
int* ptr = &ref;
cout << *ptr << endl;

What will be the output of the following code snippet?
void changeValue(int* ptr) {
    *ptr = 20;
}

int main() {
    int value = 10;
    changeValue(&value);
    cout << value << endl;
    return 0;
}

What will be the output of the following code snippet?
void changeArray(int arr[]) {
    arr[0] = 5;
}

int main() {
    int arr[3] = {1, 2, 3};
    changeArray(arr);
    cout << arr[0] << endl;
    return 0;
}

What will be the output of the following code snippet?
```cpp
int** matrix = new int*[2];
for (int i = 0; i < 2; i++) {
    matrix[i] = new int[3];
    for (int j = 0; j < 3; j++) {
        matrix[i][j] = i + j;
    }
}
cout << matrix[1][2] << endl;
```

What will be the output of the following code snippet?
```cpp
int** matrix = new int*[3];
for (int i = 0; i < 3; i++) {
    matrix[i] = new int[2];
    for (int j = 0; j < 2; j++) {
        matrix[i][j] = i * j;
    }
}
cout << matrix[2][1] << endl;
```

What will be the output of the following code snippet?

```cpp
void changeValue(int** matrix) {
    matrix[0][1] = 5;
}

int main() {
    int** matrix = new int*[2];
    for (int i = 0; i < 2; i++) {
        matrix[i] = new int[2];
        for (int j = 0; j < 2; j++) {
            matrix[i][j] = i + j;
        }
    }
    changeValue(matrix);
    cout << matrix[0][1] << endl;
    return 0;
}
```

What will be the output of the following code snippet?
 

```cpp
void changeValue(int** matrix) {
    matrix[0] = new int[2]{5, 5};
}

int main() {
    int** matrix = new int*[2];
    for (int i = 0; i < 2; i++) {
        matrix[i] = new int[2]{1, 1};
    }
    changeValue(matrix);
    cout << matrix[0][1] << endl;
    return 0;
}
```

What will be the output of the following code snippet?

```cpp
void changeValue(int*** matrix) {
    matrix[1][0][0] = 10;
}

int main() {
    int*** matrix = new int**[2];
    for (int i = 0; i < 2; i++) {
        matrix[i] = new int*[2];
        for (int j = 0; j < 2; j++) {
            matrix[i][j] = new int[2]{i, j};
        }
    }
    changeValue(matrix);
    cout << matrix[1][0][0] << endl;
    return 0;
}
```