1  pragma solidity >=0.5.0 <0.7.0;
 2  
 3  // Abstract contract for the full ERC 20 Token standard
 4  // https://github.com/ethereum/EIPs/issues/20
 5  
 6  interface ERC20Token {
 7  
 8      /**
 9       * @notice send `_value` token to `_to` from `msg.sender`
10       * @param _to The address of the recipient
11       * @param _value The amount of token to be transferred
12       * @return Whether the transfer was successful or not
13       */
14      function transfer(address _to, uint256 _value) external returns (bool success);
15  
16      /**
17       * @notice `msg.sender` approves `_spender` to spend `_value` tokens
18       * @param _spender The address of the account able to transfer the tokens
19       * @param _value The amount of tokens to be approved for transfer
20       * @return Whether the approval was successful or not
21       */
22      function approve(address _spender, uint256 _value) external returns (bool success);
23  
24      /**
25       * @notice send `_value` token to `_to` from `_from` on the condition it is approved by `_from`
26       * @param _from The address of the sender
27       * @param _to The address of the recipient
28       * @param _value The amount of token to be transferred
29       * @return Whether the transfer was successful or not
30       */
31      function transferFrom(address _from, address _to, uint256 _value) external returns (bool success);
32  
33      /**
34       * @param _owner The address from which the balance will be retrieved
35       * @return The balance
36       */
37      function balanceOf(address _owner) external view returns (uint256 balance);
38  
39      /**
40       * @param _owner The address of the account owning tokens
41       * @param _spender The address of the account able to transfer the tokens
42       * @return Amount of remaining tokens allowed to spent
43       */
44      function allowance(address _owner, address _spender) external view returns (uint256 remaining);
45  
46      /**
47       * @notice return total supply of tokens
48       */
49      function totalSupply() external view returns (uint256 supply);
50  
51      event Transfer(address indexed _from, address indexed _to, uint256 _value);
52      event Approval(address indexed _owner, address indexed _spender, uint256 _value);
53  }