Question

How to move element in array in order or remove from array?

Example: arr[3,3,2,1]

move(arr[0],arr[sizeof(arr)]);

arr[3,2,1,3];

I wrote function, but is correctly it ?

void remove(int index, char *arr)
{
    arr[index]=NULL;
    for(int i=index;i<sizeof(arr)-1;i++)
        swap(arr[i],arr[i+1]);
}

Answer 1

This already exists in the C++ standard library (std::rotate), and the C standard library (memmove)

If you’re using C++, (since it comes with a std::swap function, and C can’t swap with parameters like that):

void remove(int index, char *arr, int len)
{
    if (len<=0)
        len = strlen(arr);
    std::rotate(arr+index, arr+index+1, arr+len);
    arr[len-1] = NULL;
}

Also, in C++, use a std::vector or std::string rather than a naked char* pointer.

If you’re using C:

void remove(int index, char *arr, int len)
{
    if (len<=0)
        len = strlen(arr);
    memmove(arr+index, arr+index+1, len-index-1);
    arr[len-1] = NULL;
}

If you are using naked char* pointers, always pass a length.