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# Tangerine Network RNG Library
## Introduction
Tangerine Network provides on-chain randomness through a precompiled contract.
Using a precompiled contract instead of introducing a new OP code ensures that
we are compatible with EVM, and eliminates the need to maintain a separate
toolchain.
The precompiled contract is located at
`0xc327ff1025c5b3d2deb5e3f0f161b3f7e557579a`, which is the first 20 bytes of
`Keccak256Hash("Tangerine Network Random")`. The gas cost for each invocation is 64.
To use the random library, simply include the library file then call `Random.rand()` to get the random number.
## Example
```
import "github.com/tangerine-network/random-lib/RandomLib.sol";
contract UseRandom {
event Win();
event Lose();
function readRand() public view returns (uint256) {
return Random.rand();
}
function bet() public {
if (Random.rand() % 100 >= 50) {
emit Win();
} else {
emit Lose();
}
}
}
```
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