为什么我的Java布尔测试总是失败？

Question

我正在尝试进行布尔测试，以便如果其中一个胎压低于35或超过45，则系统会输出“不良充气”。

在我的课堂上，我必须使用布尔值，这是我尝试过的。但是，返回的布尔值始终为true。我不明白为什么。

public class tirePressure
{
    private static double getDoubleSystem1 ()  //Private routine to simply read a double in from the command line
    {
        String myInput1 = null; //Store the string that is read form the command line
        double numInput1 = 0;      //Used to store the converted string into an double
        BufferedReader mySystem; //Buffer to store input
        mySystem = new BufferedReader (new InputStreamReader (System.in)); // creates a connection to system files or cmd
        try
        {
            myInput1 = mySystem.readLine (); //reads in data from console
            myInput1 = myInput1.trim (); //trim command cuts off unneccesary inputs
        }
        catch (IOException e)  //checks for errors
        {
            System.out.println ("IOException: " + e);
            return -1;
        }

        numInput1 = Double.parseDouble (myInput1); //converts the string to an double
        return numInput1;                       //return double value to main program
    }

    static public void main (String[] args)
    {
        double TireFR; //double to store input from console
        double TireFL;
        double TireBR;
        double TireBL;
        boolean goodPressure;
        goodPressure = false;

        System.out.println ("Tire Pressure Checker");
        System.out.println (" ");

        System.out.print ("Enter pressure of front left tire:");
        TireFL = getDoubleSystem1 ();    //read in an double from the user

        if (TireFL < 35 || TireFL > 45)
        {
            System.out.println ("Pressure out of range");
            goodPressure = false;
        }

        System.out.print ("Enter pressure of front right tire:");
        TireFR = getDoubleSystem1 ();    //read in an double from the user

        if (TireFR < 35 || TireFR > 45)
        {
            System.out.println ("Pressure out of range");
            goodPressure = false;

        }

        if (TireFL == TireFR)
            System.out.print (" ");
        else
            System.out.println ("Front tire pressures do not match");
        System.out.println (" ");

        System.out.print ("Enter pressure of back left tire:");
        TireBL = getDoubleSystem1 ();    //read in an double from the user

        if (TireBL < 35 || TireBL > 45)
        {
            System.out.println ("Pressure out of range");
            goodPressure = false;
        }

        System.out.print ("Enter pressure of back right tire:");
        TireBR = getDoubleSystem1 ();    //read in an double from the user

        if (TireBR < 35 || TireBR > 45)
        {
            System.out.println ("Pressure out of range");
            goodPressure = false;
        }

        if (TireBL == TireBR)
            System.out.print (" ");
        else
            System.out.println ("Back tire pressures do not match");

        if (goodPressure = true)
            System.out.println ("Inflation is OK.");
        else
            System.out.println ("Inflation is BAD.");

        System.out.println (goodPressure);


    } //mainmethod
} // tirePressure Class

Answer 1

    if (goodPressure = true)

更改为：

    if (goodPressure == true)

甚至更好：

    if (goodPressure)

布尔比较运算符为==和!=。该=是赋值运算符。

另外，goodPressure = true;在检查是否违反条件之前，需要进行初始设置。