// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract HarrisToken {
    string public constant name = "Harris Token";
    string public constant symbol = "HARRIS";
    uint8 public constant decimals = 18;
    uint256 public immutable totalSupply;
    mapping(address => uint256) public balanceOf;
    mapping(address => mapping(address => uint256)) public allowance;

    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed owner, address indexed spender, uint256 value);

    constructor() {
        totalSupply = 100000000 * 10**uint256(decimals);
        balanceOf[msg.sender] = totalSupply;
        emit Transfer(address(0), msg.sender, totalSupply);
    }

    function safeAdd(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "Addition overflow");
        return c;
    }

    function safeSub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a, "Subtraction overflow");
        uint256 c = a - b;
        return c;
    }

    function transfer(address _to, uint256 _value) public returns (bool success) {
        require(_value > 0, "Transfer value must be greater than zero");
        require(_to != address(0), "Invalid address");
        require(balanceOf[msg.sender] >= _value, "Insufficient balance");

        balanceOf[msg.sender] = safeSub(balanceOf[msg.sender], _value);
        balanceOf[_to] = safeAdd(balanceOf[_to], _value);
        emit Transfer(msg.sender, _to, _value);
        return true;
    }

    function approve(address _spender, uint256 _value) public returns (bool success) {
        require(_spender != address(0), "Invalid address");

        allowance[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value);
        return true;
    }

    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
        require(_value > 0, "TransferFrom value must be greater than zero");
        require(_from != address(0), "Invalid address");
        require(_to != address(0), "Invalid address");
        require(balanceOf[_from] >= _value, "Insufficient balance");
        require(allowance[_from][msg.sender] >= _value, "Allowance exceeded");

        balanceOf[_from] = safeSub(balanceOf[_from], _value);
        balanceOf[_to] = safeAdd(balanceOf[_to], _value);
        allowance[_from][msg.sender] = safeSub(allowance[_from][msg.sender], _value);
        emit Transfer(_from, _to, _value);
        return true;
    }
}

{
  "compilationTarget": {
    "contracts/HarrisToken.sol": "HarrisToken"
  },
  "evmVersion": "paris",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs"
  },
  "optimizer": {
    "enabled": false,
    "runs": 200
  },
  "remappings": []
}