C program to reverse an array

C program to reverse an array: This program reverses the array elements. For example if a is an array of integers with three elements such that
a[0] = 1
a[1] = 2
a[2] = 3
Then on reversing the array will be
a[0] = 3
a[1] = 2
a[0] = 1

C programming code

#include <stdio.h>

int main()

{

   int n, c, d, a[100], b[100];

   printf("Enter the number of elements in array\n");

   scanf("%d", &n);

   printf("Enter the array elements\n");

   for (c = 0; c < n ; c++)

      scanf("%d", &a[c]);

   for (c = n - 1, d = 0; c >= 0; c--, d++)

      b[d] = a[c];

   for (c = 0; c < n; c++)

      a[c] = b[c];

   printf("Reverse array is\n");

   for (c = 0; c < n; c++)

      printf("%d\n", a[c]);

   return 0;

}

Output of program:

Enter the number of elements in array

5

Enter the array elements

2

23

362

9856

Reverse array is

9865

362

23

2

Reverse array by swapping (without using additional memory)

#include <stdio.h>

int main() {

  int array[100], n, c, t, end;

  scanf("%d", &n);

  end = n - 1;

  for (c = 0; c < n; c++) {

    scanf("%d", &array[c]);

  }

  for (c = 0; c < n/2; c++) {

    t          = array[c];

    array[c]   = array[end];

    array[end] = t;

    end--;

  }

  printf("Reversed array elements are:\n");

  for (c = 0; c < n; c++) {

    printf("%d\n", array[c]);

  }

  return 0;

}

C program to reverse an array using pointers

#include <stdio.h>

#include <stdlib.h>

void reverse_array(int*, int);

int main()

{

   int n, c, *pointer;

   scanf("%d",&n);

   pointer = (int*)malloc(sizeof(int)*n);

   if( pointer == NULL )

      exit(EXIT_FAILURE);

   for ( c = 0 ; c < n ; c++ )

      scanf("%d",(pointer+c));

   reverse_array(pointer, n);

   printf("Original array on reversal is\n");

   for ( c = 0 ; c < n ; c++ )

      printf("%d\n",*(pointer+c));

   free(pointer);

   return 0;

}

void reverse_array(int *pointer, int n)

{

   int *s, c, d;

   s = (int*)malloc(sizeof(int)*n);

   if( s == NULL )

      exit(EXIT_FAILURE);

   for ( c = n - 1, d = 0 ; c >= 0 ; c--, d++ )

      *(s+d) = *(pointer+c);

   for ( c = 0 ; c < n ; c++ )

      *(pointer+c) = *(s+c);

   free(s);

}

Array is passed to function and a new array is created and contents of passed array (in reverse order) are copied into it and finally contents of new array are copied into array passed to function.

-------------------------------**************************----------------------------------------