pointers in C

I have a little problem. way back in high school I took java, and never had to deal with these little things. now, at college, they're making me take C. I don't have anything against it, its just that.. well I'm not entirely sure what pointers are used for, or what they accomplish. would anyone care to elighten me?

Here is an example of pointer:
include <stdio.h>

int main(int argc, char **argv)
{
    int array[] = { 1, 3, 5, 7, 9 };
    printf("%d\n", 2[array]);
    return 0;
}