pragma solidity ^0.8.6;
contract mycontract{
address owner;
string name;
bool visible;
uint16 count;
constructor ()public {
owner=msg.sender;
}
function changname (stringmemory _name) public returns (stringmemory){
if(msg.sender==owner){
name=_name;
return "sucsesss";
}else{
return "acsess denid";
}
}
function showname () view public returns(stringmemory){
return name;
}
}
hey guuys i write this codes down but i gut the blow error what should i do now pls help me thank you
this project its belong to my university and if i lost in it i will fail my exam and im bechokh miram toro khoda komak konid thank you
i got some warning too what is this ?
SPDX license identifier not provided in source file. Before publishing, consider adding a comment containing "SPDX-License-Identifier: " to each source file. Use "SPDX-License-Identifier: UNLICENSED" for non-open-source code. Please see https://spdx.org for more information.
--> browser/test.sol
DeclarationError: Identifier not found or not unique.
--> browser/test.sol:14:21:
|
14 | function changname (stringmemory _name) public returns (stringmemory){
| ^^^^^^^^^^^^
It has a couple of bugs in its code.
builder visibility is not required
in the parameters of its functions it has a bad type
'stringmemory' the variable would be type 'sting' and it would be read from memory.
In this way your code would look like this:
pragma solidity ^0.8.6;
contract mycontract{
address owner;
string name;
bool visible;
uint16 count;
constructor () {
owner=msg.sender;
}
function changname (string memory _name) public returns (string memory){
if(msg.sender==owner){
name=_name;
return "sucsesss";
}else{
return "acsess denid";
}
}
function showname () view public returns(string memory){
return name;
}
}
Related
I'm new to Solidity but I can't find much information about my problem.
For example, I want to make different contracts for different functionalities (I see them as classes)
For example
Main contract
// SPDX-License-Identifier: None
pragma solidity >=0.8.6;
import "./AuthContract.sol";
contract Contract {
string public message;
constructor() {
message = "test";
}
function getMessage() public view returns(string memory) {
return message;
}
}
and second contract
contract Auth {
struct UserDetail {
address addr;
string name;
string password;
string CNIC;
bool isUserLoggedIn;
}
mapping(address => UserDetail) user;
// user registration function
function register(
address _address,
string memory _name,
string memory _password,
string memory _cnic
) public returns (bool) {
require(user[_address].addr != msg.sender);
user[_address].addr = _address;
user[_address].name = _name;
user[_address].password = _password;
user[_address].CNIC = _cnic;
user[_address].isUserLoggedIn = false;
return true;
}
// user login function
function login(address _address, string memory _password)
public
returns (bool)
{
if (
keccak256(abi.encodePacked(user[_address].password)) ==
keccak256(abi.encodePacked(_password))
) {
user[_address].isUserLoggedIn = true;
return user[_address].isUserLoggedIn;
} else {
return false;
}
}
// check the user logged In or not
function checkIsUserLogged(address _address) public view returns (bool) {
return (user[_address].isUserLoggedIn);
}
// logout the user
function logout(address _address) public {
user[_address].isUserLoggedIn = false;
}
}
How could I use the functionalities from that contract in the main contract?
Is such a thing possible in the blockchain?
I am quite new here also but i can solve your problem, if not solve i can lead you to a good path .
so firstly you said you want to create multiple contract for different functionalities, this is good but keep in my you are going to exhaust a lot of gas.
so the answer to your problem is easy you can just read it and implement it.
if you want to use a contract in the Another contract (main in your case) you can do it in two ways(according to my knowledge there might be other).
using new keyword
using address of your previously deployed contract
we will be using the First case as i suppose you havenot deployed the second contract yet
In Order to do it you can use
Auth myObj=new Auth();
This will create a new instance of the contract Auth in your main contract and now you can use the Auth contract's function in your Main contract.you can create a function copy the above line and you can use the Functions using dot operator.
myObj.register(_address,_name,moreandmore);
I believe this will solve your problem if not you can ask it.
Thank You!
I want to test the following code in Remix. But what is the procedure?
What do I put in the input field for the function labeled set?
Mapping.sol
// https://solidity-by-example.org/mapping
// Mapping
// Maps are created with the syntax mapping(keyType => valueType).
// The keyType can be any built-in value type, bytes, string, or any contract.
// valueType can be any type including another mapping or an array.
// Mappings are not iterable.
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.13;
contract Mapping {
// Mapping from address to uint
mapping(address => uint) public myMap;
function get(address _addr) public view returns (uint) {
// Mapping always returns a value.
// If the value was never set, it will return the default value.
return myMap[_addr];
}
function set(address _addr, uint _i) public {
// Update the value at this address
myMap[_addr] = _i;
}
function remove(address _addr) public {
// Reset the value to the default value.
delete myMap[_addr];
}
}
contract NestedMapping {
// Nested mapping (mapping from address to another mapping)
mapping(address => mapping(uint => bool)) public nested;
function get(address _addr1, uint _i) public view returns (bool) {
// You can get values from a nested mapping
// even when it is not initialized
return nested[_addr1][_i];
}
function set(
address _addr1,
uint _i,
bool _boo
) public {
nested[_addr1][_i] = _boo;
}
function remove(address _addr1, uint _i) public {
delete nested[_addr1][_i];
}
}
This code came from Solidity by Example.
When I implement it on Remix, I get the following screen.
At this point, to test it, I think I need to map an address to a uint256, so I enter the following in the field next to the set button:
["0xcf646ed6e21fd0756ec45a6be5e1057fc24a1b8308175ff0b9f97f565b594eb3", 7439]
The value of the address was a randomly generated hash (I suspect the random hash might be a problem?)
I expect to see the set function render the value 7439. But, instead, it throws the following error:
transact to Mapping.set errored: Error encoding arguments: Error: invalid address (argument="address", value=["0xcf646ed6e21fd0756ec45a6be5e1057fc24a1b8308175ff0b9f97f565b594eb3",7439], code=INVALID_ARGUMENT, version=address/5.5.0) (argument=null, value=["0xcf646ed6e21fd0756ec45a6be5e1057fc24a1b8308175ff0b9f97f565b594eb3",7439], code=INVALID_ARGUMENT, version=abi/5.5.0)
What am I doing wrong?
You have generated a random SHA-256 that is of the format of a valid address, but it doesn't exist on the Remix's browser-based (Javascript VM) chain as any account. If it does, you might be just lucky.
If you want to use valid addresses that do exist on the browser-based VM chain, copy and use the addresses in the account section.
I am new in Solidity and I have been trying to create and get STRUCT without adding it to an Array. I alway see Structs with arrays and the method .push and I wanted to try it without it.
I have created a single Contract with one Struct and one function to create and get it.
If I create a single public function to create, but not return, the struct it doesn´t give me any error... Like the following:
struct Todo {
string name;
uint age;
}
function createTodo(string memory _name, uint _age) public pure{
Todo memory myTodo = Todo(_name, _age);
}
With the above code I would also like to know why it wouldn´t let me set the pointer "Todo" as storage like: Todo storage myTodo = Todo(_name, _age); It gives an TypeError: Todo memory is not implicity convertible to expect type struct storage pointer.
Next, I tried to modify the function to create and RETURN but then is when I start getting the ParseError.
The code is the following:
function getTodo(string memory _name, uint _age) public returns(struct myTodo) {
Todo memory myTodo = Todo(_name, _age);
return myTodo;
}
With the aobve code I also tried in "returns(struct), returns(struct memory)"....
I would really appreciate any type of help here.
Thank you very much
You received this error because you're wrong to set a returns keyword on getTodo() function. In your case, you must change your function in this way:
function getTodo(string memory _name, uint _age) external pure returns(Todo memory) {
Todo memory myTodo = Todo(_name, _age);
return myTodo;
}
If you want to handle storage structs, see this smart contract code:
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
contract Test {
struct Todo {
string name;
uint age;
}
// Declare state variable
Todo[] todoArray;
// Push into array new struct
function createTodo(string memory _name, uint _age) public {
todoArray.push(Todo(_name, _age));
}
// Retrieve ToDo struct from specific index about struct array
function getTodo(uint _index) external view returns(Todo memory) {
return todoArray[_index];
}
}
[https://i.stack.imgur.com/uSU0Y.png][1]
from solidity:
DeclarationError: Identifier already declared.
--> contracts/MySimpleStorage.sol:16:5:
|
16 | people[] public people;
|
Note: The previous declaration is here:
--> contracts/MySimpleStorage.sol:11:5:
|
11 | struct people {
| (Relevant source part starts here and spans across multiple lines).
error 2
from solidity:
TypeError: Expected callable expression before call options.
contracts/MySimpleStorage.sol:32:21:
|
32 | people.push(people{favoriteNumber: _favoriteNumber, name: _name});
check the above link for screenshot
here's the main code
`// SPDX-License-Identifier: MIT
pragma solidity >=0.7.0 <0.9.0;
contract MySimpleStorage {
//this will get initilized to 0 since we did not state the number
uint256 public favoriteNumber;
bool favoriteBool;
struct people{
uint256 favoriteNumber;
string name;
}
People[] public people;
mapping(string => uint256) public nameToFavoriteNumber;
function store(uint256 _favoriteNumber) public {
favoriteNumber = _favoriteNumber;
}
function retrieve() public view returns(uint256) {
return favoriteNumber;
}
function addPerson(string memory _name, uint256 _favoriteNumber) public{
people.push(people(_favoriteNumber, _name));
nameToFavoriteNumber[_name] = _favoriteNumber;
}
}`
This issue is from case sensitivity. you have declared struct with lower case here -struct people
You will need to declare same before the dynamic array here-People[]
Lowercase here is your object name that appears on the button in public, and this could be anything -public people
Bottonname.push(structNAME...
solidity newbie here. when I try to read the value of the people array. I'm getting an error:
call to SimpleStorage.people errored: Error encoding arguments: Error:
invalid BigNumber string (argument="value" value=""
code=INVALID_ARGUMENT version=bignumber/5.4.2)
my compiler version is 0.6.6. not sure what's wrong? any suggestions?
// SPD-License_Identifier: MIT
pragma solidity ^0.6.0;
contract SimpleStorage {
uint256 favNum;
struct People {
uint256 favNum;
string name;
}
People[] public people;
function store(uint256 _favNum) public {
favNum = _favNum;
}
function retrieve() public view returns(uint256) {
return favNum;
}
function addPerson(string memory _name, uint256 _favNum) public {
people.push(People(_favNum, _name));
}
}
The error happens when you're trying to call the people() function (from Remix IDE) without passing any value.
Since the People[] public people is a public property, it autogenerates a getter function during compilation. But because it's an array, the getter function requires an uint256 param specifying the index of the array that you want to retrieve.
When you pass an empty string, Remix tries to encode it to the BigNumber instance, but this fails. Only when you pass an (existing) index of the array, it works correctly:
If you want to get the whole array in one call, you need to create a separate getter function:
function getAllPeople() public view returns (People[] memory) {
return people;
}
You must click on the small arrow to the right of the deploy button, then the fields will be displayed so that you can complete the data that the contract must receive.