JAVASCRIPT

get random number in solidity

// Solidity pseudo-random function:
function random() private view returns (uint) {
  // sha3 and now have been deprecated
  return uint(keccak256(abi.encodePacked(block.difficulty, block.timestamp, players)));
  // convert hash to integer
  // players is an array of entrants
}

// invoke random function in a pickWinner example function
function pickWinner() public {
  uint index=random()%players.length;
}

random function in solidity

function random() private view returns(uint){
  uint source = block.difficulty + now;
  bytes memory source_b = toBytes(source);
  return uint(keccak256(source_b)) % 100;	
}