Back in my C programming days I thought there was a constant or function (I can't remember what it was called, let's call it `SMALL`) whose value was the smallest possible positive value. (Imagine the LSB=1 and all other bits = 0.) It was used to avoid a divide by zero error. 

For example, let's say you want to compute `z = x/y`. Then you could calculate  

`z = x / (y + SMALL);`

Is there a built-in function in MS EXCEL that implements `SMALL`? For that matter, does it exist in C/C++ or am I going crazy?