java簡單計算器代碼

public class Calculator {
public static void main(String[] args) {
Calculator calculator = new Calculator(); //創建對象調用函數

    Scanner scanner = new Scanner(System.in); //創建scanner掃描對象，獲取用戶輸入數據
    System.out.println("請輸入第一個數據");
    double a=scanner.nextDouble();

    System.out.println("請輸入運算符：");
    String operator=scanner.next();

    System.out.println("請輸入第二個數據");
    double b= scanner.nextDouble();

    double result=0;//存儲最后的計算結果
    scanner.close();//關閉scanner資源

    // 根據輸入的運算符調用不同的方法
    if ("+".equals(operator)){//equals判斷字符是否相等
        result= calculator.add(a,b);
    }//調用減法
    else if ("-".equals(operator)){
        result=calculator.sub(a,b);
    }
    else if ("*".equals(operator)){
        result=calculator.multiply(a,b);
    }
    else if ("/".equals(operator)){
        result=calculator.div(a,b);
    }
    System.out.println("最終結果為"+result);

}
public double add(double a,double b){
    return a+b;
}
public double sub(double a,double b){
    return a-b;
}
public double multiply(double a, double b){
    return a*b;
}
public double div(double a, double b){
    return a/b;
}

}