Vfrdtyky

Following is a code to split an array. The

first output array will contain the input array entries in between the given two indices and the second
output array will contain the rest of the entries.

void splitArray(int *arr, int size, int ind1, int ind2,

     int *&first, int &firstSize, int *&second, int &secondSize){

    firstSize = ind2 - ind1 + 1;

    secondSize = size - firstSize;

    first = new int[firstSize];

    second = new int[secondSize];

    for (int i = 0; i < ind1; i++)

    second[i] = arr[i];

    for (int i = ind1; i <= ind2; i++)

    first[i - ind1] = arr[i];

    for (int i = ind2 + 1; i < size; i++)

    second[i - firstSize] = arr[i];

    }

The thing I can understand why it has parameters like int *&first and int *&second, arent they are same as just int first and int second but in this code they are used as pointers to dynamic arrays.

T *&foo declares a reference to a pointer to T. Don't confuse the ampersand in declarations and definitions with the address-of operator.

References to pointers are used if the called function needs to be able to modify the value of the pointer passed to it:

void bar(int *&ptr) {

    ptr = 42;  // change the value of the pointer  (pseudo ... 42 is most likely

    *ptr = 42; // change the value of the pointee   not a valid pointer value)

}



// ...



int *foo = nullptr;

bar(foo);

// foo == 42;

Hint: Read types from right to left: T *& --> &* T --> reference (&) to pointer (*) to type T.