/*
Module: bubble_sort.c
What:
-----
Sorts a list of given integers suing bubble sort algorihm.
Input: N integers separated by spaces.
Output: Sorted list of integers.
Assumption on input: valid.

How:
----
Algorithm: Bubble Sort
Data Structures: None.
*/

#include < stdio.h >

/* constants */
#define N 10 /* size of array to sort */
#define FALSE 0
#define TRUE 1

/* function prototypes */
void bubble_sort (int A [ ], int n);
void read_array (int A [ ], int n);
void write_array (int A [ ], int n);
void efficient_bubble_sort(int A [ ], int n);

int main ( ){

int array [ N ]; /* array for input */
printf ("Please enter %d decimal numbers: ", N);
read_array (array, N) ;
bubble_sort(array,N);
printf("\nThe sorted list is : ");
write_array (array, N) ;
return 0;

}
/* read_array: reads input integers into a given array
Parameters: A - the array (output).
n - number of numbers to read (input).
Returns: no return value
Algorithm: Trivial.
*/
void read_array (int A [ ], int n){
int i;
for (int i = 0; i < n; i++)
scanf("%d", &A [ i ] );

}

/* write_array: writes the contents of an array of integers
Parameters: A - the array (input).
n - number of integers to write (input).
Returns: no return value
Algorithm: Trivial.
*/
void write_array (int A [ ], int n){
int i;
for (int i = 0; i < n; i++)
printf("%d ", A [ i ] );

printf("\n");

}

/* Bubble sort: Sorts a given array of numbers in an increasing order.
Parameters: A - array to sort (input + output parameter)
n - size of the array (input parameter)
Returns: no return value.
Algorithm: Bubble Sort.
*/
void bubble_sort(int A[ ], int n){
int i; /* location of the current minimum.*/
int j; /* used to bubble i'th minimum to place.*/
int temp;
for (i = 0; i < n-1; i++){
for (j = n - 1 ; j > i; j--){ /* now A[0..i-1] is already sorted */

if ( A [ j ] < A [ j - 1 ] ){

temp = A [ j ];
A [ j ] = A [ j - 1 ];
A [ j - 1 ] = temp;

}

}

}

}

/* Bubble sort: Sorts a given array of numbers in an increasing order.
Pameters: A - array to sort (input + output parameter)
n - size of the array (input parameter)
Returns: no return value.
Algorithm: Bubble Sort - stop when there was no change
in the previous iteration.
*/
void efficient_bubble_sort(int A[], int n){

int i; /* location of the current minimum.*/
int j; /* used to bubble i'th minimum to place.*/
int change; /* flag denoting whether there was any swap*/ /* in the last iteration.*/
int temp;
change = TRUE;
i = 0 ;
while (( i < n - 1) && change){

/* as long as there was a swap in previous iteration apply an
iteration of bubble sort to array A between i and n - 1 */
change = FALSE;
for (j = n - 1 ; j > i; j --) { /* now A[0..i-1] is already sorted */
if (A [ j ] < A [ j - 1 ] ) {
temp = A [ j ];
A [ j ] = A [ j - 1 ];
A [ j - 1 ] = temp;
change = TRUE;

}

}
i++;

}

}