Binary Search C

binary_search.c

#include<stdio.h>
#include<stdlib.h>
/* Just a sample binary search in C */

int binary_search(int sought_value, int* array, int array_size) {
	int left,right=(0,array_size);
	int middle;
	while (left <= right) {
		middle = (left + right) / 2;
		if (array[middle] == sought_value) {
			return middle; }
		if (array[middle] < sought_value) {
			left = middle + 1;  }
		else {
			right = middle - 1; }
	}
	return -1; }

int main() {
	/* We will search inside an array of even numbers */
	int* even_numbers = (int *)malloc(sizeof(*even_numbers) * 10);
	int even_index = 0;
	for (even_index=0; even_index<10; even_index++) {
		even_numbers[even_index] = 2 * even_index; }

	/* And test some numbers, with both under- and overflow */
	int* test_numbers = (int *)malloc(sizeof(*test_numbers) * 10);
	int test_index = 0;
	for (test_index=0; test_index<10; test_index++) {
		test_numbers[test_index] = -2 + test_index*4;  }

	/* Perform actual tests: */
	int search_index=0;
	for (search_index=0; search_index<10; search_index++) {
		printf("Search for %d returned %d\n",test_numbers[search_index],binary_search(test_numbers[search_index],even_numbers,10));
	} 
}

Looks good to me other than
int left,right=(0,array_size); should be
int left = 0, right = array_size - 1;

For readability, you could have statically initialized the arrays:
int even_numbers[] = {0,2,4,6,8,10,12,14,16,20};
int test_numbers[] = {-2,2,6,12,16,20,24};

and for the test,
binary_search(test_numbers[i], even_numbers, sizeof(even_numbers)/sizeof(int));