Teehee

#include <stdio.h>
#include <stdlib.h>

#define MAX_LENGTH 100
#define SIZE 15
#define FOR(i, n) for(i = 0; i < n; i++)

/**
 * So sorry, my keyboard does not have the backslash key.
 */
void displayMessage(char* message);
int getPositiveInt();
int getInt();
int compareInDescOrder(const void *a, const void *b);
void getElement(int *array, int size);
int getTheSecondLargestNumber(int *array, int size, int *secondOne);

int main() {
  int array[SIZE + 1];
  int secondLargestNum, isFound;

  getElement(array, SIZE);

  if(!getTheSecondLargestNumber(array, SIZE, &secondLargestNum)) {
    displayMessage("All elements in this array are the same.");
    return 1;
  }

  printf("The second biggest element is %d\n", secondLargestNum);
  return 0;
}

int getTheSecondLargestNumber(int *array, int size, int *secondOne) {
  int i;

  qsort(array, SIZE, sizeof(int), compareInDescOrder);
  FOR(i, SIZE) {
    if(array[i] != array[0]) {
      *secondOne = array[i];
      return 1;
    }
  }
  return 0;
}

void getElement(int *array, int size) {
  int i;

  if(size < 2) {
    displayMessage("It's stupid if you want to find a second largest element in the array like this.");
    return;
  }

  displayMessage("Please enter an array:");
  FOR(i, size) {
    printf("Element #%d: ", i + 1);
    array[i] = getPositiveInt();
  }
}

int getPositiveInt() {
  int res;
  while((res = getInt()) < 0) {
    displayMessage("Please enter a positive integer!");
  }
  return res;
}

int getInt() {
  int res;
  while(scanf("%d", &res) != 1) {
    displayMessage("Please enter an integer!");
    while(getchar() != '\n');
  }
  while(getchar() != '\n');
  return res;
}

int compareInDescOrder(const void *a, const void *b) {
  int *x = (int*)a;
  int *y = (int*)b;
  return *y - *x;
}

void displayMessage(char* message) {
  if(NULL == message) return;
  printf("%s\n", message);
}