[Lec. #7] Exc. 5

#include <stdio.h>

void reverse(int* arr, int n);
void swap(int* ptr1, int* ptr2);
void rev_rec(int* arr, int n);

void main()
{
    int array[] = { 1,2,3,4,5 };

    int * arr;

    arr = array;

    int i;

    printf("\nStart of program\n\n");

    printf("Array before program:\n");

    for (i = 0; i < sizeof(array) / sizeof(int); i++)
        printf("%d ", array[i]);


    //reverse( arr, sizeof(array) / sizeof(int));
    rev_rec(arr, sizeof(array) / sizeof(int));

    printf("\n\nArray after program:\n");

    for (i = 0; i < sizeof(array) / sizeof(int); i++)
        printf("%d ", array[i]);
}

void reverse(int* arr, int n)
{
    int temp, i;

    for (i = 0; i < n / 2; i++)
        swap(&arr[i], &arr[n - 1 - i]);
}

void swap(int* ptr1, int* ptr2)
{
    int temp;

    temp = *ptr1;
    *ptr1 = *ptr2;
    *ptr2 = temp;
}

void rev_rec(int* arr, int n)
{
    if (n > 1)
    {
        swap(arr, arr + n - 1);

        rev_rec(arr + 1, n - 2);
    }
}