ReactCalculator

import React, {useState, useEffect} from 'react';

import '../Css/Calculator.css'

const Calculator = () => {

    let [result, setResultState] = useState(0)

    let [inputDisplay, setInputDisplayState] = useState(0)

    let buttonHandler = (num) =>{
        if (inputDisplay === 0){
            setInputDisplayState(
                inputDisplay = String(num)
            )
        } 
        else {
        setInputDisplayState(
            inputDisplay += String(num)
        )
        }
    }

    let evaluateResult = ()=>{

    }

    return (

        <div>
        <div className='header'>
            <h2>{result}</h2>
            <h1>{inputDisplay}</h1>


        </div>

        <div>
            <button onClick={()=>buttonHandler('1')}>1</button>
                <button onClick={() => buttonHandler('2')}>2</button>
                <button onClick={() => buttonHandler('3')}>3</button>
                <button onClick={() => buttonHandler('+')}>+</button>
                <button onClick={evaluateResult}>=</button>
        </div>


        </div>
    )
};

export default Calculator;