Java将double转换为int

Question

I have this code, and the input in the textfield is 50, so its output should be 25,
but there is a error, because no output

button_1.addActionListener(new ActionListener() {
    String tfg = textField.getText().toString();
    String tfc = textField.getText();

    public void actionPerformed(ActionEvent e) {
        if(textField.getText().toString().equals("0") || 
            textField.getText().toString().equals("") || 
            textField.getText().toString().equals(" ") || 
            textField.getText().toString().matches("[a-zA-Z]+")) {
            JOptionPane.showMessageDialog(Cow.this,
                            "Tree Amount Should Be 1 or More",
                            "Invalid Tree Amount",
                            JOptionPane.ERROR_MESSAGE);
        }

        if(!tfg.equals("0")) {
            try {
                int tfgg = Integer.parseInt(tfc);
                int trcs = tfgg * 1;
                double trcp = 1 / 2;
                int trcc = (int) trcp * trcs;
                System.out.println(new Integer(trcc).toString());
            } catch (NumberFormatException se) {

            }
        }
    }
});

I try to convert from my php to that code, here is my php code :

$doorSeed = $mount * 1;
$doorPrice = 1 / 2;
$doorConvert = $doorPrice * $doorSeed;
echo "Treasure Chest Seed = ".$doorSeed." Price : ".$doorConvert." World Lock <br>";

Answer 1

int trcc = (int) trcp * trcs;

Try this instead

int trcc = (int) (trcp * trcs);

You need to cast the complete expression [ (trcp * trcs) ] instead of just the first variable trcp to int . The other variable in the expression trcs is of double type, so the result of the expression become double . That is why you cast the complete expression. So your end result will be int

     int tfgg = Integer.parseInt(tfc.trim());    // tfc = 4;   tfgg = 4;
     int trcs = tfgg * 1;                 // trcs = 4 * 1 = 5;
     double trcp = 1.0 / 2;               // trcp = 0.5;
     int trcc = (int) (trcp * trcs);      // trcc = (0.5 * 5) = (2.5) = 2;
     System.out.println(trcc);            // 2;

double trcp = 1.0 / 2;

Here make at least one value as double so the expression will be evaluated as double as suggested by @tunaki.

Also you don't need this statement in your code int trcs = tfgg * 1; .

Use like this:

  String tfg ;
  String tfc ;
  public void actionPerformed(ActionEvent e) {
    tfg = textField.getText();
    tfc = textField.getText();
    if(textField.getText().equals("0") || textField.getText().equals("") || textField.getText().equals(" ") || textField.getText().matches("[a-zA-Z]+")) {
      JOptionPane.showMessageDialog(Cow.this,
          "Tree Amount Should Be 1 or More",
          "Invalid Tree Amount",
          JOptionPane.ERROR_MESSAGE);
    }
    if(!tfg.equals("0")) {
      try {
        int tfgg = Integer.parseInt(tfc.trim());    // tfc = 4;
        int trcs = tfgg;                 // trcs = 4 * 1 = 5
        double trcp = 1.0 / 2;                 // trcp = 0.5
        int trcc = (int) (trcp * trcs);      // trcc = (0.5 * 5) = (2.5) = 2
        System.out.println("HI: "+trcc);
      } catch (NumberFormatException ignored) {
      }

Answer 2

Your problem is at this line:

double trcp = 1 / 2;

This does not result in trcp = 0.5 but trcp = 0.0 , because you are dividing integer values (and so are using integer division).

You should use the following code:

double trcp = 1.0 / 2;

to force division using doubles.

Other comments:

• new Integer(trcc).toString() should be replaced with String.valueOf(trcc) .
• Avoid using empty catch statements: at minimum, log the exception
• What's the point of this line: int trcs = tfgg * 1; ?

Answer 3

Basically you have this (int)0.5 = 0 . In your case, trcp = 0.5 and is double, so when it's cast to integer the result is 0.

And when you do (int)a + b , the true operation with parenthesis for priority here is: ((int)a)+(b) , so what you have to is the following:

int trcc = (int) (trcp * trcs);

instead of the following:

int trcc = (int) trcp * trcs;