how to use parseInt()

[Jherald Lacambra]

where should i equate the Interger.parseInt();? :roll: :roll: :roll:

[Yosi Hendarsjah]

Hi Jherald,
Can you rephrase your question or make it more detail?

[Ramaswamy Narayanan]

In java, we can change any data type to string by adding with a string.
if i have the String
int i=0;
String str=""+i;

now the value of i is 10 and the value of str also i.
we can perform mathematical operation on i and not str eventhouth str is an integer.
so we have to convert the str to an integer format.
for that
int x=Integer.parseInt(str);
then the x contains integer variable.

The solution is
from the string having the integer value, we can get integer using the parseInt funtion.

[Jherald Lacambra]

thnx for the reply

when i use this:

int num = Integer.parseInt(text2);

the error generated was:

java.lang.NumberFormatException: For input string: " "

at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48)

at java.lang.Integer.parseInt(Integer.java)

at java.lang.Integer.parseInt(Integer.java:518)

at mypackage.Calculator$16.actionPerformed(Calculator.java:183)

at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1786)

at javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(AbstractButton.java:1839)

at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:420)

at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:258)

at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:245)

at java.awt.Component.processMouseEvent(Component.java:5100)

at java.awt.Component.processEvent(Component.java:4897)

at java.awt.Container.processEvent(Container.java:1569)

at java.awt.Component.dispatchEventImpl(Component.java:3615)

at java.awt.Container.dispatchEventImpl(Container.java:1627)

at java.awt.Component.dispatchEvent(Component.java)

at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java)

at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3198)

at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3128)

at java.awt.Container.dispatchEventImpl(Container.java:1613)

at java.awt.Component.dispatchEvent(Component.java)

at java.awt.EventQueue.dispatchEvent(EventQueue.java:458)

at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:201)

at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:137)

at java.awt.EventDispatchThread.run(EventDispatchThread.java:100)

java.lang.NumberFormatException: For input string: " "

at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48)

at java.lang.Integer.parseInt(Integer.java)

at java.lang.Integer.parseInt(Integer.java:518)

at mypackage.Calculator$16.actionPerformed(Calculator.java:183)

at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1786)

at javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(AbstractButton.java:1839)

at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:420)

at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:258)

at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:245)

at java.awt.Component.processMouseEvent(Component.java:5100)

at java.awt.Component.processEvent(Component.java:4897)

at java.awt.Container.processEvent(Container.java:1569)

at java.awt.Component.dispatchEventImpl(Component.java:3615)

at java.awt.Container.dispatchEventImpl(Container.java:1627)

at java.awt.Component.dispatchEvent(Component.java)

at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java)

at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3198)

at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3128)

at java.awt.Container.dispatchEventImpl(Container.java:1613)

at java.awt.Component.dispatchEvent(Component.java)

at java.awt.EventQueue.dispatchEvent(EventQueue.java:458)

at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:201)

at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:137)

at java.awt.EventDispatchThread.run(EventDispatchThread.java:100)

java.lang.NumberFormatException: For input string: " "

at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48)

at java.lang.Integer.parseInt(Integer.java)

at java.lang.Integer.parseInt(Integer.java:518)

at mypackage.Calculator$16.actionPerformed(Calculator.java:183)

at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1786)

at javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(AbstractButton.java:1839)

at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:420)

at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:258)

at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:245)

at java.awt.Component.processMouseEvent(Component.java:5100)

at java.awt.Component.processEvent(Component.java:4897)

at java.awt.Container.processEvent(Container.java:1569)

at java.awt.Component.dispatchEventImpl(Component.java:3615)

at java.awt.Container.dispatchEventImpl(Container.java:1627)

at java.awt.Component.dispatchEvent(Component.java)

at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java)

at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3198)

at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3128)

at java.awt.Container.dispatchEventImpl(Container.java:1613)

at java.awt.Component.dispatchEvent(Component.java)

at java.awt.EventQueue.dispatchEvent(EventQueue.java:458)

at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:201)

at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:137)

at java.awt.EventDispatchThread.run(EventDispatchThread.java:100)

java.lang.NumberFormatException: For input string: " "

at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48)

at java.lang.Integer.parseInt(Integer.java)

at java.lang.Integer.parseInt(Integer.java:518)

at mypackage.Calculator$16.actionPerformed(Calculator.java:183)

at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1786)

at javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(AbstractButton.java:1839)

at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:420)

at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:258)

at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:245)

at java.awt.Component.processMouseEvent(Component.java:5100)

at java.awt.Component.processEvent(Component.java:4897)

at java.awt.Container.processEvent(Container.java:1569)

at java.awt.Component.dispatchEventImpl(Component.java:3615)

at java.awt.Container.dispatchEventImpl(Container.java:1627)

at java.awt.Component.dispatchEvent(Component.java)

at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java)

at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3198)

at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3128)

at java.awt.Container.dispatchEventImpl(Container.java:1613)

at java.awt.Component.dispatchEvent(Component.java)

at java.awt.EventQueue.dispatchEvent(EventQueue.java:458)

at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:201)

at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:137)

at java.awt.EventDispatchThread.run(EventDispatchThread.java:100)

java.lang.NumberFormatException: For input string: " "

at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48)

at java.lang.Integer.parseInt(Integer.java)

at java.lang.Integer.parseInt(Integer.java:518)

at mypackage.Calculator$16.actionPerformed(Calculator.java:183)

at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1786)

at javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(AbstractButton.java:1839)

at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:420)

at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:258)

at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:245)

at java.awt.Component.processMouseEvent(Component.java:5100)

at java.awt.Component.processEvent(Component.java:4897)

at java.awt.Container.processEvent(Container.java:1569)

at java.awt.Component.dispatchEventImpl(Component.java:3615)

at java.awt.Container.dispatchEventImpl(Container.java:1627)

at java.awt.Component.dispatchEvent(Component.java)

at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java)

at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3198)

at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3128)

at java.awt.Container.dispatchEventImpl(Container.java:1613)

at java.awt.Component.dispatchEvent(Component.java)

at java.awt.EventQueue.dispatchEvent(EventQueue.java:458)

at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:201)

at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:137)

at java.awt.EventDispatchThread.run(EventDispatchThread.java:100)

java.lang.NumberFormatException: For input string: " "

at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48)

at java.lang.Integer.parseInt(Integer.java)

at java.lang.Integer.parseInt(Integer.java:518)

at mypackage.Calculator$16.actionPerformed(Calculator.java:183)

at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1786)

at javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(AbstractButton.java:1839)

at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:420)

at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:258)

at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:245)

at java.awt.Component.processMouseEvent(Component.java:5100)

at java.awt.Component.processEvent(Component.java:4897)

at java.awt.Container.processEvent(Container.java:1569)

at java.awt.Component.dispatchEventImpl(Component.java:3615)

at java.awt.Container.dispatchEventImpl(Container.java:1627)

at java.awt.Component.dispatchEvent(Component.java)

at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java)

at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3198)

at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3128)

at java.awt.Container.dispatchEventImpl(Container.java:1613)

at java.awt.Component.dispatchEvent(Component.java)

at java.awt.EventQueue.dispatchEvent(EventQueue.java:458)

at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:201)

at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:137)

at java.awt.EventDispatchThread.run(EventDispatchThread.java:100)

java.lang.NumberFormatException: For input string: " "

at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48)

at java.lang.Integer.parseInt(Integer.java)

at java.lang.Integer.parseInt(Integer.java:518)

at mypackage.Calculator$16.actionPerformed(Calculator.java:183)

at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1786)

at javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(AbstractButton.java:1839)

at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:420)

at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:258)

at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:245)

at java.awt.Component.processMouseEvent(Component.java:5100)

at java.awt.Component.processEvent(Component.java:4897)

at java.awt.Container.processEvent(Container.java:1569)

at java.awt.Component.dispatchEventImpl(Component.java:3615)

at java.awt.Container.dispatchEventImpl(Container.java:1627)

at java.awt.Component.dispatchEvent(Component.java)

at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java)

at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3198)

at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3128)

at java.awt.Container.dispatchEventImpl(Container.java:1613)

at java.awt.Component.dispatchEvent(Component.java)

at java.awt.EventQueue.dispatchEvent(EventQueue.java:458)

at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:201)

at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:137)

at java.awt.EventDispatchThread.run(EventDispatchThread.java:100)

java.lang.NumberFormatException: For input string: " "

at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48)

at java.lang.Integer.parseInt(Integer.java)

at java.lang.Integer.parseInt(Integer.java:518)

at mypackage.Calculator$16.actionPerformed(Calculator.java:183)

at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1786)

at javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(AbstractButton.java:1839)

at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:420)

at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:258)

at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:245)

at java.awt.Component.processMouseEvent(Component.java:5100)

at java.awt.Component.processEvent(Component.java:4897)

at java.awt.Container.processEvent(Container.java:1569)

at java.awt.Component.dispatchEventImpl(Component.java:3615)

at java.awt.Container.dispatchEventImpl(Container.java:1627)

at java.awt.Component.dispatchEvent(Component.java)

at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java)

at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3198)

at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3128)

at java.awt.Container.dispatchEventImpl(Container.java:1613)

at java.awt.Component.dispatchEvent(Component.java)

at java.awt.EventQueue.dispatchEvent(EventQueue.java:458)

at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:201)

at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:137)

at java.awt.EventDispatchThread.run(EventDispatchThread.java:100)

java.lang.NumberFormatException: For input string: " "

at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48)

at java.lang.Integer.parseInt(Integer.java)

at java.lang.Integer.parseInt(Integer.java:518)

at mypackage.Calculator$16.actionPerformed(Calculator.java:183)

at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1786)

at javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(AbstractButton.java:1839)

at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:420)

at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:258)

at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:245)

at java.awt.Component.processMouseEvent(Component.java:5100)

at java.awt.Component.processEvent(Component.java:4897)

at java.awt.Container.processEvent(Container.java:1569)

at java.awt.Component.dispatchEventImpl(Component.java:3615)

at java.awt.Container.dispatchEventImpl(Container.java:1627)

at java.awt.Component.dispatchEvent(Component.java)

at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java)

at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3198)

at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3128)

at java.awt.Container.dispatchEventImpl(Container.java:1613)

at java.awt.Component.dispatchEvent(Component.java)

at java.awt.EventQueue.dispatchEvent(EventQueue.java:458)

at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:201)

at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:137)

at java.awt.EventDispatchThread.run(EventDispatchThread.java:100)

java.lang.NumberFormatException: For input string: " "

at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48)

at java.lang.Integer.parseInt(Integer.java)

at java.lang.Integer.parseInt(Integer.java:518)

at mypackage.Calculator$16.actionPerformed(Calculator.java:183)

at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1786)

at javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(AbstractButton.java:1839)

at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:420)

at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:258)

at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:245)

at java.awt.Component.processMouseEvent(Component.java:5100)

at java.awt.Component.processEvent(Component.java:4897)

at java.awt.Container.processEvent(Container.java:1569)

at java.awt.Component.dispatchEventImpl(Component.java:3615)

at java.awt.Container.dispatchEventImpl(Container.java:1627)

at java.awt.Component.dispatchEvent(Component.java)

at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java)

at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3198)

at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3128)

at java.awt.Container.dispatchEventImpl(Container.java:1613)

at java.awt.Component.dispatchEvent(Component.java)

at java.awt.EventQueue.dispatchEvent(EventQueue.java:458)

at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:201)

at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:137)

at java.awt.EventDispatchThread.run(EventDispatchThread.java:100)

java.lang.NumberFormatException: For input string: " "

at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48)

at java.lang.Integer.parseInt(Integer.java)

at java.lang.Integer.parseInt(Integer.java:518)

at mypackage.Calculator$16.actionPerformed(Calculator.java:183)

at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1786)

at javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(AbstractButton.java:1839)

at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:420)

at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:258)

at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:245)

at java.awt.Component.processMouseEvent(Component.java:5100)

at java.awt.Component.processEvent(Component.java:4897)

at java.awt.Container.processEvent(Container.java:1569)

at java.awt.Component.dispatchEventImpl(Component.java:3615)

at java.awt.Container.dispatchEventImpl(Container.java:1627)

at java.awt.Component.dispatchEvent(Component.java)

at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java)

at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3198)

at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3128)

at java.awt.Container.dispatchEventImpl(Container.java:1613)

at java.awt.Component.dispatchEvent(Component.java)

at java.awt.EventQueue.dispatchEvent(EventQueue.java:458)

at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:201)

at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:137)

at java.awt.EventDispatchThread.run(EventDispatchThread.java:100)

Process exited with exit code 0.

[Ramaswamy Narayanan]

i need extra information about the 'text2' variable.
is it a String variable contains integer data?

[Jherald Lacambra]

static String text2 = new String();
Calculator.text2 = Calculator.txt.getText();
int num = Integer.parseInt(text2);

[Yosi Hendarsjah]

From the error code we can see that variable text2 contains only a space. So it can't be converted into integer.

[David Harkness]

Originally posted by Jherald Lacambra:
int num = Integer.parseInt(text2);

the error generated was:

java.lang.NumberFormatException: For input string: " "

This is telling you that the String text2 contains a single space and that's it. This is not a valid integer. To handle bad input, you can use a try/catch block.

int num = 0;  // default to zero if bad input
try {
    num = Integer.parseInt(text2);
}
catch ( NumberFormatException e ) {
    System.out.println("'" + text2 + "' is not a valid integer");
    // use default of zero above
}

[Jherald Lacambra]

my string has not yet been initialize till my button is pressed so how can it contain space?..
is there some other possibility for the errors?

[David Harkness]

Can you post more of the surrounding code? How about printing out the value before converting it into an int (put |s or "s around it so you can see if it's empty or null or a space).

Um, why are you converting it before it has a value? That will always fail. Also, if it were null (uninitialized), I believe parseInt will throw a NullPointerException (read the JavaDocs to be sure).

[Jherald Lacambra]

thanks for your reply.. but i manage a different way of solving it