Dinos problems

problemVersion1/1/problem1.txt

@@ -1,9 +1,10 @@
 // SPDX-License-Identifier: MIT
 pragma solidity ^0.8.17;
 
-// Declare public state variables as command, then assign the default value of that type.
+// Declare public state variables, then assign the default value of that type.
+// In fact you do not to assign the default value cuz it's "default"
 contract answer1 {
-    // TODO: declare a uint variable named myUint
+    // TODO: declare a uint256 variable named myUint
 
     // TODO: declare a boolean variable named myBool
 
@@ -12,7 +13,11 @@ contract answer1 {
     // TODO: declare a string variable named myString
 
 
-    function getUint() public view returns (uint) {
+
+
+    // --------------Below are judging functions-------------------
+
+    function getUint() public view returns (uint256) {
       return myUint;
     }
     function getBool() public view returns (bool) {

problemVersion1/10/problem10.txt

@@ -1,7 +1,9 @@
 // SPDX-License-Identifier: MIT
 pragma solidity ^0.8.17;
 
+
 // The system will deploy `Called` for you
+// The interface you are going to write will be use to call contract `Called`.
 contract Called {
   bool public called = false;
 
@@ -13,7 +15,9 @@ contract Called {
   }
 }
 
-// TODO: write an interface named `ICalled`, implement the two functions in contract `Called`. 
+// TODO 1: write an interface named `ICalled`, implement the two functions which is in contract `Called`. 
+
+
 
 
 contract answer10 {
@@ -24,10 +28,14 @@ contract answer10 {
   }
 
   function setCalled() external {
-    // TODO: finish this function by using `ICalled` to call `setCalled()` in contract `Called`. 
+    // TODO 2: Finish this function by using `ICalled` to call `setCalled()` in contract `Called`. 
+
 
   }
 
+
+  // --------------Below are judging functions-------------------
+
   function checkAns() external view returns (bool) {
     return ICalled(address(calledContract)).getCalled();
   }

problemVersion1/11/problem11.txt

@@ -23,12 +23,16 @@ contract answer11 {
     called = new Called();
   }
 
-  // TODO: Declare a function named `sendETHtoCalled`.
+  // TODO 1: Declare a function named `sendETHtoCalled`.
+
+
   // This function should send 50000 wei to the contract `called` using method `call`
   // Assign the first return value to `success`.
   // Notice that there are multiple return values of method call. 
 
 
+  // --------------Below are judging functions-------------------
+
   function checkAns() external view returns(uint256) {
     require(success, "transfer not success");
     return called.getBalance();

problemVersion1/12/problem12.txt

@@ -17,17 +17,24 @@ contract answer12 {
   Called public called;
   bool public success; 
 
+
+
+  // TODO: write a function named `callSetGreet()`, take a string as a param.
+
+
+
+  // This function should call function `setGreet()` in contract `called` and a string as param. 
+  // You can, but not required, send some ETH with this call .
+
+
+
+  // --------------Below are judging functions-------------------
+
   receive() external payable {}
 
   function deployContract() external {
     called = new Called();
   }
-
-  // TODO: write a function named `callSetGreet()`, taking a string as a parameter.
-  // This function should call function `setGreet()` in contract `called` and input the param string. 
-  // You can, but not required, send some ETH with this call .
-
-
   function getGreet() external view returns (string memory) {
     return called.getGreet();
   }

problemVersion1/13/problem13.txt

@@ -2,15 +2,20 @@
 pragma solidity ^0.8.17;
 
 contract answer13 {
-  // TODO: Define a struct named `Food`, 
-  // The first variable is a string named `name`, and the second is a uint256 named `price`.
+  // TODO 1: Define a struct named `Food`, 
+  // This struct includes a string named `name`, and a uint256 named `price`.
 
-  // TODO: Declare a Food array named `foods`
 
-  // TODO: Declare a function named `createFood()`, it should let user createNewFood. 
-  // That is, it should take a string and a uint256 as param, create a `Food`, and push it into the array `foods`.
+  // TODO 2: Declare a Food array named `foods`
 
 
+  // TODO 3: Declare a function named `createFood()` 
+  //         It should take a string and a uint256 as param, create a `Food`, and push it into the array `foods`.
+
+
+
+  // --------------Below are judging functions-------------------
+
   function checkAns() external view returns (string memory, uint256) {
     return (foods[0].name, foods[0].price);
   }

problemVersion1/16/problem16.txt

@@ -1,6 +1,8 @@
 // SPDX-License-Identifier: MIT
 pragma solidity ^0.8.17;
 
+// In this problem, we are going to write our ERC20 contract !
+
 interface IERC20 {
   event Transfer(address indexed from, address indexed to, uint256 value);
 
@@ -12,15 +14,15 @@ interface IERC20 {
 
   function transfer(address to, uint256 amount) external returns (bool);
 
-  // The functions below are commented for judging/compiling reasons.
+  // ---------functions below are commented for compiling reasons.--------
   // function allowance(address owner, address spender) external view returns (uint256);
 
   // function approve(address spender, uint256 amount) external returns (bool);
 
   // function transferFrom(address from, address to, uint256 amount) external returns (bool);
 }
 
-// Finish the functions below, you can have a peek to the interface if you feel it difficult.
+// Finish the functions below, you can take a look at the interface if you find it difficult.
 contract answer16 is IERC20 {
     mapping(address => uint256) private _balances;
     mapping(address => mapping(address => uint256)) private _allowances;
@@ -34,10 +36,13 @@ contract answer16 is IERC20 {
 
     // Finish the `totalSupply` function, it should return the totalSupply of this ERC20 token.
 
+
     // Finish the `balanceOf` function, it should return the balance of an input address.
 
+
     // Finish the `transfer` function, it should transfer specific amount of ETH from the function called to another address and return true.
 
+
 }
 
 

problemVersion1/17/problem17.txt

@@ -2,7 +2,8 @@
 pragma solidity ^0.8.17;
 
 // Cont'd
-// Finish the ERC20
+// If you haven't done the part 1, it is recommended first
+// Finish the ERC20 contract
 interface IERC20 {
   event Transfer(address indexed from, address indexed to, uint256 value);
 
@@ -49,7 +50,8 @@ contract answer17 is IERC20 {
 
     //========= All the Todos are below here ==========
 
-    // TODO: Finish the function `allowance`, it should return the allowance from owner to spender.
+    // TODO 1: Finish the function `allowance`, it should return the allowance from owner to spender.
+
 
 
 
@@ -63,19 +65,21 @@ contract answer17 is IERC20 {
         require(_owner != address(0), "ERC20: approve from the zero address");
         require(spender != address(0), "ERC20: approve to the zero address");
 
-        // TODO: set the allowance from `owner` to `sender` to be `amount`
+        // TODO 2: set the allowance from `owner` to `sender` to be `amount`
 
-        // TODO: fire the event `Approval`
+        // TODO 3: fire the event `Approval`
 
 
     }
 
-    // TODO: Finish function `transferFrom`
+    // TODO 4: Finish function `transferFrom`
     // It should call `_spendAllowance()` and `_transfer()`, try to pass in the correct param !
 
 
 
-    // ========== All todos are done ! Good job =======
+
+
+  // --------------Below are judging functions-------------------
 
     function _spendAllowance(address _owner, address spender, uint256 amount) internal virtual {
         uint256 currentAllowance = _allowances[owner][spender];

problemVersion1/18/answer18.sol

@@ -22,10 +22,6 @@ contract answer18 is IERC165, IAnother {
 
     function aFunction() external returns (bool) {}
     function bFunction() external returns (bool) {}
-
-    function getIAnotherId() external pure returns(bytes4) {
-      return this.aFunction.selector ^ this.bFunction.selector;
-    }
 }
 
 

problemVersion1/18/problem18.txt

@@ -7,19 +7,20 @@ interface IERC165 {
 }
 
 interface IAnother {
-  function aFunction() external returns (bool);
-  function bFunction() external returns (bool);
+    function aFunction() external returns (bool);
+    function bFunction() external returns (bool);
 }
 
 
 contract answer18 is IERC165, IAnother {
 
-  // TODO: write a function named `supportsInterface` which takes a bytes4 as an input.
-  // This function check if the input interfaceID is supported by this contract.
-  // Note that `answer18` contract supports two interface: IERC165 and IAnother.
+    // TODO: write a function named `supportsInterface` which takes a bytes4 as an input.
+    // This function check if the input interfaceID is supported by this contract.
+    // Note that `answer18` contract supports two interface: IERC165 and IAnother.
 
 
 
+
     function aFunction() external returns (bool) {}
     function bFunction() external returns (bool) {}
 }

problemVersion1/19/problem19.txt

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: MIT
 pragma solidity ^0.8.17;
 
+// ERC721! We are going to write our own ERC721 contract.
 interface IERC165 {
     function supportsInterface(bytes4 interfaceID) external view returns (bool);
 }
@@ -26,17 +27,17 @@ contract ERC721 is IERC721 {
       interfaceId == type(IERC165).interfaceId;
   }
 
-  // TODO: write a `_mint` internal function taking an address and an id
+  // TODO 1: write a `_mint` internal function taking an address and an id
   // It should revert with "mint to zero address" message if so
   // It should revert with "already minted" message if so
   // it should emit Transfer
 
 
-  // TODO: write an `ownerOf` external function.
+  // TODO 2: write a `ownerOf` external function.
   // It should revert with "token doesn't exist" if so
 
 
-  // TODO: write an `balanceOf` external function.
+  // TODO 3: write a `balanceOf` external function.
   // It should revert with "owner = zero address" if someone query for zero address
 
 
@@ -48,6 +49,6 @@ contract answer19 is ERC721 {
   function mint(address to, uint256 id) external {
     _mint(to, id);
   }
-
+  
 }
 

problemVersion1/2/problem2.txt

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: MIT
 pragma solidity ^0.8.17; 
-// Below you have to declare public functions, remember to assign the type of functions( pure or view )
+// Declare public functions, remember to assign the type of functions, that is, pure or view.
 contract answer2 { 
     uint public x = 1;
 

problemVersion1/20/problem20.txt

@@ -1,6 +1,8 @@
 // SPDX-License-Identifier: MIT
 pragma solidity ^0.8.17;
 
+// Cont'd
+// If you haven't done part 1, it is recommended to do it first.
 interface IERC165 {
     function supportsInterface(bytes4 interfaceID) external view returns (bool);
 }
@@ -88,19 +90,21 @@ contract ERC721 is IERC721 {
             spender == _approvals[id]);
   }
 
-  // write a function named `transferFrom`
+  // TODO 1: write a function named `transferFrom`
   // it should transfer token if all requirement are satisfied
   // it should revert with "transfer to zero address" message if so
   // it should fire event `Transfer`
 
 
 
-  // write a function named `_burn` taking one uint256 as param
+  // TODO 2:  write a function named `_burn` taking one uint256 as param
   // It should burn token
   // it should revert with "not minted" if so
   // it should emit `Transfer` as it transfer token to zero address
 
 
+
+
 }
 
 contract answer20 is ERC721 {

problemVersion1/3/problem3.txt

@@ -1,10 +1,10 @@
 // SPDX-License-Identifier: MIT
 pragma solidity ^0.8.17; 
 
-// complete the function below
+// Complete the function below.
 contract answer3 { 
     function biggerThanTen(uint256 num) public pure returns (bool) {
-        // if the input is bigger than ten, return true, else return false
+        // If the input is bigger than ten, return true, else return false
 
     }
 }

problemVersion1/4/answer4.sol

@@ -2,21 +2,21 @@
 pragma solidity ^0.8.17; 
 contract answer4 { 
     mapping(address => uint256) balanceOf;
-    mapping(address => mapping(uint256 => bool)) AddressOwnNum;
+    mapping(address => mapping(uint256 => bool)) addressOwnNum;
 
     function setBalanceOf(address _user, uint256 _balance) public {
       balanceOf[_user] = _balance;
     }
 
     function setAddressOwnNFT(address _user, uint256 _num) public {
-      AddressOwnNum[_user][_num] = true;
+      addressOwnNum[_user][_num] = true;
     }
 
     function getBalanceOf(address _user) public view returns (uint256) {
       return balanceOf[_user];
     }
 
     function getAddressOwnNum(address _user, uint256 _num) public view returns (bool) {
-      return AddressOwnNum[_user][_num];
+      return addressOwnNum[_user][_num];
     }
 }