public/subjects/blockchain/usable-token

Usable Token

Instructions

• Complete the following Smart Contract named UsableToken
• Like MinimalToken, its constructor takes as parameter an amount that is given initially to the deployer account.
• Create a function transfer(address, uint) that allows the owner to transfer a certain amount of tokens to the specified address.
• Create a function approve(address, uint) that allows the owner of the token to approve a spender to spend a certain amount of tokens.
• The allowance states should keep track of the amount of tokens that a spender can spend on behalf of the owner.

contract UsableToken {
    ... public accounts;
    ... public allowance;

    constructor(uint256 initialNumber) {
        ...
    }

    function transfer(address to, uint256 amount) public {
        ...
    }

    function approve(address spender, uint256 amount) public {
        ...
    }

    function transferFrom(address from, address to, uint256 amount) public {
    }
}

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