50 lines
1.6 KiB
Rust
50 lines
1.6 KiB
Rust
use ethers::{types::U256, utils::format_units};
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use std::ops::{Div, Mul};
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fn main() {
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let a = U256::from(10);
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let b = U256::from(2);
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// addition
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let sum = a + b;
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assert_eq!(sum, U256::from(12));
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// subtraction
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let difference = a - b;
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assert_eq!(difference, U256::from(8));
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// multiplication
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let product = a * b;
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assert_eq!(product, U256::from(20));
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// division
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let quotient = a / b;
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assert_eq!(quotient, U256::from(5));
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// modulo
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let remainder = a % b;
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assert_eq!(remainder, U256::zero()); // equivalent to `U256::from(0)`
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// exponentiation
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let power = a.pow(b);
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assert_eq!(power, U256::from(100));
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// powers of 10 can also be expressed like this:
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let power_of_10 = U256::exp10(2);
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assert_eq!(power_of_10, U256::from(100));
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// Multiply two 'ether' numbers:
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// Big numbers are integers, that can represent fixed point numbers.
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// For instance, 1 ether has 18 fixed
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// decimal places (1.000000000000000000), and its big number
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// representation is 10^18 = 1000000000000000000.
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// When we multiply such numbers we are summing up their exponents.
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// So if we multiply 10^18 * 10^18 we get 10^36, that is obviously incorrect.
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// In order to get the correct result we need to divide by 10^18.
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let eth1 = U256::from(10_000000000000000000_u128); // 10 ether
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let eth2 = U256::from(20_000000000000000000_u128); // 20 ether
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let base = U256::from(10).pow(18.into());
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let mul = eth1.mul(eth2).div(base); // We also divide by 10^18
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let s: String = format_units(mul, "ether").unwrap();
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assert_eq!(s, "200.000000000000000000"); // 200
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}
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