can anyone explain lesson 4 remix fund me getprice function

[pjamy]

how does the decimal system work and why is it 1e10

[krakxn]

Do not worry, it is very simple.

Anything which follows the e is essentially equivalent to this:

e1 -> 10 to the power of 1 -> 10^1
e2 -> 10 to the power of 2 -> 10^2
For you, e10 -> 10 to the power of 10 -> 10^10

So, anything which follows the e is the exponent, and e itself is the base (10)

So, 1e10 = 1 multiplied by e10 (or, 10^10)

[alymurtazamemon]

@pjamy

In the getPrice function we first get the latest price of ETH from Chainlink price feed priceFeed.latestRoundData();. It returns multiple things, but we only need the price so we get it like this (,int256 price,,,).

The price return by price feed is in int256 so we type caste it to uint256. Inside it, we multiply price with 1e10, because price feed returns price with 8 decimals so we multiply it with 1e10 to make it equivalent to Wei unit that is 1e18. As @krakxn mentioned above 1e10 is nothing just power of 10, similarly 1e18 is a power of 18.

Hope it clears your query!