TestToken.sol

pragma solidity ^0.6.1;

contract TestToken{

    string public name='Test Token';
    string public symbol='Test';
    string public standard ='Test Token v1.0';
    uint256 public totalSupply;

    event Transfer(
         address indexed _from,
         address indexed _to,
         uint256 _value;
    )

    event Approval(
        address indexed _owner,
        address indexed _spender,
        uint256 _value;
    )

    mapping(address=>uint256) public balanceOf;
    mapping(address=>mapping(address=>uint256)) public alllowance;

    function TestToken() public{

        uint _initialSupply=100000;
        balanceOf[msg.sender]=_initialSupply;
        totalSupply=_initialSupply;
    }

    function transfer(address _to,uint256 _value) public returns(bool success){
        require(balanceOf[msg.sender]>=_value);

        balanceOf[msg.sender]-=_value;
        balanceOf[_to]=_value;

        Transfer(msg.sender,_to,_value);

        return true;
    }

    function approve(address _spender,uint256 _value ) public returns (bool success){
        allowance[msg.sender][_spender]=_value;

        Approval(msg.sender,_spender,_value);

        return true;
    }

    function transferFrom(address _from,address _to,uint256 _value) public returns(bool success){

        require(_value<=balanceOf[_from]);
        require(_value<=allowance[_from][msg.sender]);

        balanceOf[_from] -=_value;
        balanceOf[_from][msg.sender]-=_value;

        allowance[_from][msg.sender]-=_value;

        Transfer(_from,_to,_value);

        return true;

    }

}