Cheaper Gas

contracts/example/FunWithStorage.sol

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+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.7;
+
+contract FunWithStorage {
+    uint256 favoriteNumber; // Stored at slot 0
+    bool someBool; // Stored at slot 1
+    uint256[] myArray; /* Array Length Stored at slot 2,
+    but the objects will be the keccak256(2), since 2 is the storage slot of the array */
+    mapping(uint256 => bool) myMap; /* An empty slot is held at slot 3
+    and the elements will be stored at keccak256(h(k) . p)
+
+    p: The storage slot (aka, 3)
+    k: The key in hex
+    h: Some function based on the type. For uint256, it just pads the hex
+    */
+    uint256 constant NOT_IN_STORAGE = 123;
+    uint256 immutable i_not_in_storage;
+
+    constructor() {
+        favoriteNumber = 25; // See stored spot above // SSTORE
+        someBool = true; // See stored spot above // SSTORE
+        myArray.push(222); // SSTORE
+        myMap[0] = true; // SSTORE
+        i_not_in_storage = 123;
+    }
+
+    function doStuff() public {
+        uint256 newVar = favoriteNumber + 1; // SLOAD
+        bool otherVar = someBool; // SLOAD
+        // ^^ memory variables
+    }
+}