CODEWITHSUNDEEP
ethereumsolidity
MadeBy Alvaropop
MadeBy Alvaropop

Reputation: 91

Identifier not found or not unique?

I made a solidity contract and when I compiled it, I got the following error: 'DeclarationError: Identifier not found or not unique. --> Token.sol:20:59: | 20 | function balanceOf(address owner) public view returns(unit) { | ^^^^' What's up with that?

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.2;

contract Token { 
    mapping(address => uint) public balances;
    mapping(address => mapping(address => uint)) public allowance;
    
    uint public totalSupply = 1000000 * 10 ** 18;
    string public name = "Mebium";
    string public symbol = "MEB";
    uint public decimals = 18;
    
    event Transfer(address indexed from, address indexed to, uint value);
    event Approval (address indexed owner, address indexed spender, uint value);
    
    constructor() {
        balances[msg.sender] = totalSupply;
    }
    
    function balanceOf(address owner) public view returns(unit) {
        return balances[owmer];
    }
    
    function transfer(address to, uint value) public returns(bool) {
        require(balanceOf(msg.sender) >= value, 'balance too low');
        balances[to] += value;
        balances[msg.sender] -= value;
        emit Transfer(msg.sender, to, value);
        return true;
    }
    
    function transferFrom(address from, address to, uint value) public returns(bool) {
        require(balanceOf(from) >= value, 'balance too low');
        require(allowance[from][msg.sender] >= value, 'allowance too low');
        balances[to] += value;
        balances[from] -= value;
        emit Transfer(from, to, value);
        return true;
        
    }
    
    function approve(address spender, uint value) public returns(bool) {
        allowance[msg.sender][spender] = value;
        emit Approval(msg.sender, spender, value);
        return true;
    }
}

Upvotes: 0

Views: 2263

Answers (1)

Petr Hejda
Petr Hejda

Reputation: 43591

It's caused by a typo in your code. The return type should be uint (unsigned integer), not unit.

You have one more typo in the function - should be owner, is owmer.

function balanceOf(address owner) public view returns(uint) {
    return balances[owner];
}

Upvotes: 1

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