# % (Modulo)

## Category
Arithmetic

## Arity
**Binary** — left operand % right operand.

```
<number> % <number>
```

## Description
Returns the remainder after dividing the left operand by the right operand. Auto-unwraps `shared` values before operating.

**Modulo by zero throws `SqTypeError`.**

## How It Works
Performs `double` floating-point modulo via `a % b = a - b * floor(a / b)`. This matches C# `%` behavior for doubles, not truncated integer remainder. The host checks for zero divisor.

## Usage

### Basic modulo
```sqf
_result = 10 % 3;             // 1
_remainder = 17 % 5;          // 2
_isEven = (_num % 2) == 0;
```

### Wrap-around / cycling
```sqf
_index = (_index + 1) % _arrayCount;  // wrap index
_angle = _angle % 360;                // normalize angle
```

### Periodic checks
```sqf
// Run every 5th frame
if (_frame % 5 == 0) then {
    doPeriodicWork();
};
```

## Errors
- **`SqTypeError`** — thrown when divisor is `0`.

## Thread Safety
Not atomic. Regular modulo on primitives is thread-safe.

## See Also
- [/](div.md) — division
- [floor](floor.md) — floor rounding
- [round](round.md) — nearest integer