circular_movement_of_array_elements.c

/*

    circular_movement_of_array_elements.c


    You can find all my C programs at Dragan Milicev's pastebin:

    https://pastebin.com/u/dmilicev

*/

#include <stdio.h>


// Displays an array of n integers
void display_array_of_integers( char text[], int arr[], int n )
{
    int i;

    printf("%s ( n = %d )\n\n", text, n );

    for( i=0; i<n ; i++ )       // display of n array items
        printf("%4d", arr[i] );

    printf("\n");

} // display_array_of_integers()


// make array of integers from 0 to n-1
void form_array( int arr[], int n )
{
    int i;

    for( i=0; i<n ; i++ )
        arr[i] = i;

} // form_array()


// From the end of the array to the left,
// it moves the array elements one place to the right
void circular_move_array_elements_one_place_to_the_right( int arr[], int n )
{
    int mem;                    // place in memory to remember one integer
    int i = n-1;                // i is an index of last one array member

    mem = arr[n-1];             // remember last element of array

    while( i > 0 )   // go through the array backwards, from the last member to the first
    {
        arr[i] = arr[i-1];      // push one element to the right
        i--;                    // going backwards, we reduce the index
    }
                                // the first place is now empty
    arr[i] = mem;               // now in first place is last element

} // circular_move_array_elements_one_place_to_the_right()


// From the end of the array to the left,
// it moves the array elements one place to the right
void circular_move_array_elements_k_places_to_the_right( int arr[], int n, int k )
{
    int i;

    for( i=0; i<k ; i++ )
        circular_move_array_elements_one_place_to_the_right( arr, n );

} // circular_move_array_elements_one_place_to_the_right()



int main(void)
{
    int arr[100];               // array of 100 integers
    int i, n, k;

    printf("\n Enter number of array elements, n = ");
    scanf("%d",&n);

    printf("\n How many places to the right circularly move the elements, k = ");
    scanf("%d",&k);

    form_array( arr, n );

    display_array_of_integers( "\n Before:  ", arr, n );

    circular_move_array_elements_k_places_to_the_right( arr, n, k );

    display_array_of_integers( "\n After:  ", arr, n );


    return 0;

} // main()