为什么我的代码在 remix 上显示 pragma 错误？

Question

I'm practicing with some open codes. also I'm pretty new on solidity. When i try to compile my code, it keep getting this Error: browser/grow.sol:1:1: Warning: Source file does not specify required compiler version! Consider adding "pragma solidity ^0.5.0;" ^ . I'm using REMIX & compiler version 0.5.0

    /**
 *Submitted for verification at Etherscan.io on 2020-08-25
*/

pragma solidity ^0.5.0;

contract ERC20Interface {
    function totalSupply() 
        public 
        view 
        returns (uint);

    function balanceOf(address tokenOwner) 
        public 
        view 
        returns (uint balance);
    
    function allowance
        (address tokenOwner, address spender) 
        public 
        view 
        returns (uint remaining);

    function transfer(address to, uint tokens)              public 
        returns (bool success);
    
    function approve(address spender, uint tokens)      public 
        returns (bool success);

    function transferFrom 
        (address from, address to, uint tokens)                 public 
        returns (bool success);


    event Transfer(address indexed from, address indexed to, uint tokens);
    event Approval(address indexed tokenOwner, address indexed spender, uint tokens);
    
    
}

contract SafeMath {
    function safeAdd(uint a, uint b) public pure returns (uint c) {
        c = a + b;
        require(c >= a);
    }
    function safeSub(uint a, uint b) public pure returns (uint c) {
        require(b <= a); c = a - b; } function safeMul(uint a, uint b) public pure returns (uint c) { c = a * b; require(a == 0 || c / a == b); } function safeDiv(uint a, uint b) public pure returns (uint c) { require(b > 0);
        c = a / b;
    }
}


contract MYTOKEN is ERC20Interface, SafeMath {
    string public name;
    string public symbol;
    uint8 public decimals; 
    
    uint256 public _totalSupply;
    
    mapping(address => uint) balances;
    mapping(address => mapping(address => uint)) allowed;

    constructor() public {
        name = "MYTOKEN";
        symbol = "MYT";
        decimals = 18;
        
        _totalSupply = 1000000000000000000000000;
        
        balances[msg.sender] = _totalSupply;
        emit Transfer(address(0), msg.sender, _totalSupply);
    }
    
    
    function totalSupply() public view returns (uint) {
        return _totalSupply - balances[address(0)];
    }
    
    function balanceOf(address tokenOwner) public view returns (uint balance) {
        return balances[tokenOwner];
    }

    function allowance(address tokenOwner, address spender) public view returns (uint remaining) {
        return allowed[tokenOwner][spender];
    }

    function approve(address spender, uint tokens) public returns (bool success) {
        allowed[msg.sender][spender] = tokens;
        emit Approval(msg.sender, spender, tokens);
        return true;
        
    }
    
    function transfer(address to, uint tokens) public returns (bool success) {
        balances[msg.sender] = safeSub(balances[msg.sender], tokens);
        balances[to] = safeAdd(balances[to], tokens);
        emit Transfer(msg.sender, to, tokens);
        return true;
    }
    
    function transferFrom(address from, address to, uint tokens) public returns (bool success) {
        balances[from] = safeSub(balances[from], tokens);
        allowed[from][msg.sender] = safeSub(allowed[from][msg.sender], tokens);
        balances[to] = safeAdd(balances[to], tokens);
        emit Transfer(from, to, tokens);
        return true;
    }
    
}

Answer 1

No errors on my side. Have you tried to recompile your code once you've haded the pragma statement? In remix, you can recompile your code in the SOLIDITY COMPILER section (left side of the screen). Sometimes error stays until code is recompiled.