---
name: "swapbddvar"
section: "3"
platform: "linux"
package: "alliance"
version: "5.1.1-3"
release: "Debian 10 (Buster)"
platforms: ["linux"]
url: "https://new.carta.tech/swapbddvar"
---

# swapbddvar(3)

swaps two contiguous variables.

## NAME

swapbddvar - swaps two contiguous variables.

## SYNOPSYS

```
#include "bdd101.h"
void swapbddvar( BddSystem, Variable )
  bddsystem ∗BddSystem;
  bddvar     Variable;
```

## PARAMETERS

- *BddSystem*

  The **bdd** system.

- *Variable*

  The variable to swap.

## DESCRIPTION

**swapbddvar** swaps the variable number *Variable* with the variable number *Variable* + 1, in the **bdd** system *BddSystem*. If a null pointer is given, the default **bdd** system is used. This function is usefull for the **bdd** nodes reordering.\

## RETURN VALUE

**swapbddvar** returns nothing.

## ERRORS

**"variable xxx out of range, error !"**

The *Variable* and *Variable* + 1, must be valid variables number.

## EXAMPLE

```
#include "bdd101.h"
   bddsystem  ∗BddSystem;
   bddnode    ∗BddNode1;
   bddnode    ∗BddNode2;
   BddSystem  = createbddsystem( 100, 1000, 100, 50000 );
   BddNode1 = addbddvar( (bddsystem ∗)0, 0 );
   BddNode2 = addbddvar( (bddsystem ∗)0, 0 );
   swapbddvar( (bddsystem ∗)0, 0 );
   destroybddsystem( (bddsystem ∗)0 );
```

## SEE ALSO

[**bdd**(1)](/bdd/1.md)