Quicksort implementation using a 3 way partition. In C

quicksort.c

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

void exchange_values(int input_array[], int left_index, int right_index){
	int temp_value = input_array[left_index];
	input_array[left_index] = input_array[right_index];
	input_array[right_index] = temp_value;
	return;
}

int is_sorted(int input_array[], int size_of_array){
	int i ;
	for(i = 0; i < size_of_array - 1; i ++){
		if(input_array[i] > input_array[i+1]){
			return -1;
		}
	}
	return 1;
}

void quick_sort(int input_array[], int bottom_bound, int upper_bound){
	if(upper_bound <= bottom_bound){
		return;
	}
	int lowest_index = bottom_bound;
	int i = bottom_bound + 1;
	int top_index = upper_bound;
	int pivot = input_array[bottom_bound];

	while(i <= top_index){
		if(input_array[i] < pivot){
			exchange_values(input_array, lowest_index++, i++);
		}else if(input_array[i] >= pivot){
			exchange_values(input_array, i, top_index--);
		}else{
			i++;
		}
	}
	quick_sort(input_array, bottom_bound, lowest_index - 1);
	quick_sort(input_array, top_index + 1, upper_bound);
}

int main(int argc, char* argv[]){
	/* code */
	int size_of_array = 1000000;
	int input_array[size_of_array];
	int i;
	for(i = 0; i < size_of_array; i++){
		input_array[i] = rand() % 10000;
	}
	quick_sort(input_array, 0, size_of_array);
	if(is_sorted(input_array, size_of_array) > 0){
		printf("Is sorted\n");
	}else{
		printf("Not sorted\n");
	}
	return 0;
}