年份比较工具的逻辑错误

Question

我正在尝试创建一个工具，将当前年份与事件发生的年份进行比较，然后允许用户猜测自该事件发生以来已经过去了多少年。例如，首届FRC锦标赛于1992年举行。今年是2015年。用户猜测它发生在 23 年前，这是正确的。

所以，在我看来，代码看起来像这样......

  public class Credits extends Activity {
    int inaugural = 1992;
    int guess;
    int differenceInYears;
    Calendar calendar = Calendar.getInstance();
    int year = calendar.get(Calendar.YEAR);
    int output;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_credits);
        final EditText yearGuess=(EditText)findViewById(R.id.txtYearGuess);
        Button go = (Button)findViewById(R.id.btnCalculate);
        final TextView result = ((TextView)findViewById(R.id.txtResult));
        go.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                int userGuess= Integer.parseInt(yearGuess.getText().toString());
                differenceInYears = year - inaugural;
                output = userGuess - differenceInYears;
                if (output < 1) {
                    result.setText("Guess again! You guessed too low!");
                }
                else if (output == 1) {
                    result.setText("You're REALLY close!");
                }
                else if (output == -1) {
                    result.setText("You're REALLY close!");
                }
                else if (output > 1) {
                    result.setText("Guess again! You guessed too high!");
                }
                else {
                    result.setText("Good job! You're an FRC Genious!");
                }
            }
        });
     }
    }

。但是，这些值在测试时继续出错。我在这里错过了什么？我的数学有问题吗？还是代码？还是两者兼而有之？

Answer 1

它与你的 if 语句的逻辑有关。当用户猜对时，"output"应该等于 0，这将被您的第一个条件捕获。

Answer 2

简单的逻辑错误。

if (output < 1) {
                    result.setText("Guess again! You guessed too low!");
                }

应该是...

if (output < -1) {
                    result.setText("Guess again! You guessed too low!");
                }

只是忘了让低比较负。