C Program for Binary Search

 int BinarySearch(int *array, int number_of_elements, int key)
 {
      int low = 0, high = number_of_elements-1, mid;
      while(low <= high)
      {
          mid = (low + high)/2;
          if(array[mid] < key)
          {
                  low = mid + 1;
          }
          else if(array[mid] == key)
          {
                  return mid;
          }
          else if(array[mid] > key)
          {
                  high = mid-1;
          }
      }
      return -1;
 }
 int main()
 {
      int number_of_elements;
      scanf("%d",&number_of_elements);
      int array[number_of_elements];
      int iter;
      for(iter = 1;iter < number_of_elements;iter++)
      {
          if(array[iter]< array[iter - 1])
          {
                 printf("Given input is \n not sorted\n");
 return 0;
          }
      }
      int key;
      scanf("%d",&key);
/* Calling this functions searches for the key and returns its index. It returns -1 if key is not found.*/
      int index;
      index = BinarySearch(array,number_of_elements,key);
     if(index==-1)
     {
              printf("Element not found\n");
     }
     else
     {
             printf("Element is at index %d\n ",index);
     }
     return 0;
 }