Ethereum Cookbook

How to do it…

1. You can set your own time duration for providing the bonus. In this recipe, we will provide a 20% bonus to those investors who buy within the first 24 hours of the sale starting.
2. Create constant state variables to store the bonus percentage and time duration:

uint public bonusPercent = 20;uint public bonusDuration = 1 days;

3. Create a different function to calculate the bonus. It should return the number of bonus tokens, if any, and zero if not applicable:

function calculateBonus(uint _toknes) public view    returns (uint bonusTokens) {    // calculate bonus}

4. Add a condition to check whether the buyer buys a token on the first day:

function calculateBonus(uint _toknes) public view    returns (uint bonusTokens) { if(block.timestamp ...