how to write a state in react code example

Example 1: how to define state in react function

import React, { useState } from 'react';

function Example() {
  // Declare a new state variable, which we'll call "count" 
  const [count, setCount] = useState(0);
  return (
    <div>
      <p>You clicked {count} times</p>
      <button onClick={() => setCount(count + 1)}>
        Click me
      </button>
    </div>
  );
}

Example 2: state in react

class BalanceInquiry extends Component {
  constructor(props) {
    super(props);
    this.state = {
      totalIncome: 0,
    };
  }

  render() {
    return <div>totalIncome {this.state.totalIncome}</div>;
  }
}