二分查找

#include

int binary_search(int array[], int value, int size)
{
    int found = 0;
    int high = size, low = 0, mid;
    mid = (high + low) /2;
    printf("\n\nLooking for %d\n",value);
    while ((!found) && (high >= low))
    {
        printf("Low : %d, Mid : %d, High : %d\n",low, mid, high);
        if (value == array[mid])
            found = 1;
        else if (value < array[mid])
        {
            high = mid - 1;
            mid = (high + low) / 2;
        }
        else
            low = mid + 1;
            mid = (high + low) / 2;
    }
    return (found) ? mid : -1;
}
int main(void)
{
    int array[100], i;
    for (i = 0; i < 100; i++)
        array[i] = i+1;
    printf("%d:\n",binary_search(array, 72, 100));
    printf("%d:\n",binary_search(array, 33, 50));
    printf("%d:\n",binary_search(array, 1001, 100));
    return 0;
}