## C, sort, pancake_sort.c

``````// Sorting of array list using pancake sort
#include <stdio.h>
#include <stdlib.h>

/* Reverses the array */
void flip(int arr[], int i)
{
int temp, start = 0;

while (start < i)
{
temp = arr[start];
arr[start] = arr[i];
arr[i] = temp;
start++;
i--;
}
}

// Returns index of the maximum element in arr[0..n-1]
int findMax(int arr[], int n)
{
int maxElementIdx, i;

for (maxElementIdx = 0, i = 0; i < n; ++i)
if (arr[i] > arr[maxElementIdx])
maxElementIdx = i;

return maxElementIdx;
}

// Sorts the array using flip operations
void pancakeSort(int *arr, int n)
{
// Start from the complete array and one by one reduce current size by one
for (int curr_size = n; curr_size > 1; --curr_size)
{
// Find index of the maximum element in arr[0..curr_size-1]
int maxElementIdx = findMax(arr, curr_size);

// Move the maximum element to end of current array if it's not already
// at the end
if (maxElementIdx != curr_size - 1)
{
// To move at the end, first move maximum number to beginning
flip(arr, maxElementIdx);

// Now move the maximum number to end by reversing current array
flip(arr, curr_size - 1);
}
}
}

// Displays the array, passed to this method
void display(int arr[], int n)
{
for (int i = 0; i < n; i++)
{
printf("%d ", arr[i]);
}

printf("\n");
}

#define N 50

// Driver program to test above function
int main()
{
int arr[N];
for (int i = 0; i < N; i++)
arr[i] = rand() % (N << 1); /* random numbers from 0 to 2N */

printf("Original array: ");
display(arr, N);

pancakeSort(arr, N);
printf("Sorted array: ");
display(arr, N);

return 0;
}``````