[yom]

Yes, BIG_FLOAT and BIG_INT are too big, use printf("%f %d", BIG_FLOAT, BIG_INT); to see what's wrong. The values shouldn't be bigger than the value of cellmax.

For testing, remove all 'stock' prefixes and be sure to test all functions you provide

Also, there are tons of useful functions from the topic of the same name, maybe you should include some of them ?