How do I correctly declare an address variable in Solidity?

Question

I am a novice to Solidity so you will have to bear with me regarding the following question:

I am trying to compile my first smart contract and keep on running into this Declaration issue. How do I correctly declare an address variable in Solidity?

Find below my simple code:

// SPDX-License-Identifier: GPL-3.0

pragma solidity >=0.7.0 <0.9.0;

/**
 * @title Owner
 * @dev Set & change owner
 */
contract Gifter {

    address private gifter;
    //address private giftRecipient;
    
    // event for EVM logging
    event OwnerSet(address indexed gifter, address indexed giftRecipient);
    
    // modifier to check if caller is owner
    modifier isGifter() {
        require(msg.sender == gifter, "Gift NOT yours to give away!");
        _;
    }
    
    /**
     * @dev Set contract deployer as owner
     */
    constructor() {
        gifter = msg.sender; // 'msg.sender' is sender of current call, contract deployer for a constructor
        emit OwnerSet(address(0), gifter);
    }

    /**
     * @dev Change owner
     */
    function giftTo( address giftRecipient ) public isGifter {
        emit OwnerSet(gifter, giftRecipient);
        //gifter = giftRecipient;
        giftRecipient = giftRecipient;
    }

    /**
     * @dev Return owner address 
     * @return address of owner
     */
    function whoWasGifted() external view returns (address) {
        return giftRecipient;
    }
}

I keep getting the following error message:

DeclarationError: Undeclared identifier.
--> contracts/gifter.sol:45:16
|
45 | return giftRecipient;
| ^

Answer 1

Your giftRecipient declaration is commented out.

// SPDX-License-Identifier: GPL-3.0

pragma solidity >=0.7.0 <0.9.0;

/**
 * @title Owner
 * @dev Set & change owner
 */
contract Gifter {

    address private gifter;
    address private giftRecipient;
    
    // event for EVM logging
    event OwnerSet(address indexed gifter, address indexed giftRecipient);
    
    // modifier to check if caller is owner
    modifier isGifter() {
        require(msg.sender == gifter, "Gift NOT yours to give away!");
        _;
    }
    
    /**
     * @dev Set contract deployer as owner
     */
    constructor() {
        gifter = msg.sender; // 'msg.sender' is sender of current call, contract deployer for a constructor
        emit OwnerSet(address(0), gifter);
    }

    /**
     * @dev Change owner
     */
    function giftTo( address _giftRecipient ) public isGifter {
        emit OwnerSet(gifter, _giftRecipient);
        //gifter = giftRecipient;
        giftRecipient = _giftRecipient;
    }

    /**
     * @dev Return owner address 
     * @return address of owner
     */
    function whoWasGifted() external view returns (address) {
        return giftRecipient;
    }
}

Noticed how I change the name for the function parameter to be _giftRecipient to avoid problems with the declared one.