NoBey/openzeppelin-contracts
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Update crowdsales.md (#1821)

Browse Source 
Correct typo: 
2 * 0.5e18 = 10^18 = 1e18
This commit is contained in:
Andrew B Coathup
2019-07-16 02:33:36 +10:00
committed by Francisco Giordano
parent d95ca12415
commit f13d140ba7
1 changed files with 1 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
docs/crowdsales.md
View File

@ -39,7 +39,7 @@ In Ether, the smallest unit of the currency is wei, and `1 ETH === 10^18 wei`. I
What people usually call "one token" is actually a bunch of TKNbits, displayed to look like `1 TKN`. This is the same relationship that Ether and wei have. And what you're _always_ doing calculations in is **TKNbits and wei**. What people usually call "one token" is actually a bunch of TKNbits, displayed to look like `1 TKN`. This is the same relationship that Ether and wei have. And what you're _always_ doing calculations in is **TKNbits and wei**.
So, if you want to issue someone "one token for every 2 wei" and your decimals are 18, your rate is `0.5e17`. Then, when I send you `2 wei`, your crowdsale issues me `2 * 0.5e17 TKNbits`, which is exactly equal to `10^18 TKNbits` and is displayed as `1 TKN`. So, if you want to issue someone "one token for every 2 wei" and your decimals are 18, your rate is `0.5e18`. Then, when I send you `2 wei`, your crowdsale issues me `2 * 0.5e18 TKNbits`, which is exactly equal to `10^18 TKNbits` and is displayed as `1 TKN`.
If you want to issue someone "`1 TKN` for every `1 ETH`", and your decimals are 18, your rate is `1`. This is because what's actually happening with the math is that the contract sees a user send `10^18 wei`, not `1 ETH`. Then it uses your rate of 1 to calculate `TKNbits = rate * wei`, or `1 * 10^18`, which is still `10^18`. And because your decimals are 18, this is displayed as `1 TKN`. If you want to issue someone "`1 TKN` for every `1 ETH`", and your decimals are 18, your rate is `1`. This is because what's actually happening with the math is that the contract sees a user send `10^18 wei`, not `1 ETH`. Then it uses your rate of 1 to calculate `TKNbits = rate * wei`, or `1 * 10^18`, which is still `10^18`. And because your decimals are 18, this is displayed as `1 TKN`.