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Solidity Editor23 lines

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;
 
contract Counter {
    uint256 public count;
 
    event CountChanged(uint256 newCount);
 
    function increment() public {
        count += 1;
        emit CountChanged(count);
    }
 
    function decrement() public {
        require(count > 0, "Counter: cannot decrement below zero");
        count -= 1;
        emit CountChanged(count);
    }
 
    function getCount() public view returns (uint256) {
        return count;
    }
}

Countersolidity ^0.8.19

Functions(3)

increment()publicnonpayable

decrement()publicnonpayable

getCount()publicview→ uint256

Events(1)

CountChanged(uint256 newCount)

State Variables(1)

countuint256public

Smart Analysis6 items

Consider `immutable` for count

The state variable "count" appears to be set only once. Marking it as `immutable` saves gas by embedding the value in bytecode.

Use `external` for increment()

"increment" appears to only be called externally. Using `external` instead of `public` saves gas because external functions can read arguments directly from calldata.

Use `external` for decrement()

"decrement" appears to only be called externally. Using `external` instead of `public` saves gas because external functions can read arguments directly from calldata.

Use `external` for getCount()

"getCount" appears to only be called externally. Using `external` instead of `public` saves gas because external functions can read arguments directly from calldata.

Use Custom Errors Instead of Require Stringsline 15

Custom errors (introduced in Solidity 0.8.4) are cheaper than require strings and provide better error information.

Contract Summary

Counter has 3 functions, 1 event, 1 state variable, and 5 total elements.

Fun Fact

Solidity function selectors are the first 4 bytes of the keccak256 hash of the function signature. That's how the EVM knows which function to call!

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