> For the complete documentation index, see [llms.txt](https://guide.cronuszen.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://guide.cronuszen.com/gpcscripting/gpc-script-guide/data-and-persistence/dynamic-indexes.md).

# Dynamic indexes

The compiler can reject a constant out-of-range index. It cannot prove every runtime path:

```cpp
function curve_value(i) {
    if(i < 0) i = 0;
    if(i >= sizeof(CURVE)) i = sizeof(CURVE) - 1;
    return CURVE[i];
}
```

When an index expression includes a function call, store the result first. The compiler can warn that a dynamic index call might be evaluated twice.


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