do-while循环中的java语义问题

Question

我的程序由解方程和询问用户是否想解更多方程组成，因此，即使我输入yes继续，但循环终止，这是我的代码

 public static void main(String[] args) {

    String goAgain;

    double A, B, C, solution;
    Scanner scanner = new Scanner(System.in);
    System.out.println("This program will print a solution of an equation");
    System.out.println("of the form A*X*X + B*X + C = 0, where A, B, and");
    System.out.println("C are values that you enter.");

    do {
        System.out.println();
        System.out.println("Enter values of A, B and C : ");
        System.out.print(" A = ");
        A = scanner.nextDouble();
        System.out.print(" B = ");
        B = scanner.nextDouble();
        System.out.print(" C = ");
        C = scanner.nextDouble();
        System.out.println();
        try {

            solution = root(A, B, C);
            System.out.println("your solution is : " + solution);


        } catch (IllegalArgumentException e) {
            System.out.println("Sorry, I can't find a solution.");
            System.out.println(e.getMessage());

        }
        System.out.println("Do you want to solve another equation ? ");
        goAgain = scanner.next();
        System.out.println(goAgain);

    } while (goAgain == "yes");
}

Answer 1

在while (goAgain == "yes");中使用.equals()函数而不是==
应该是while (goAgain.equals("yes");
记住goAgain == "yes"总是返回false