Trying to convert String to Integer

Question

I am trying to convert an string into int to see the result but i am getting runtime error.

String string="Java"; 
int see=Integer.parseInt("string");

and also tried for this code-

 String[] sstring={"Java"};
 int ssee=Interger.parseInt("sstring[0]");

and also tried for this code-

 String[] sstring={"Java"};
 int ssee=Interger.parseInt(sstring[0]);

Massage which I got-

Exception in thread "main" java.lang.NumberFormatException: For input string: "string"
 at java.lang.NumberFormatException.forInputString(Unknown Source)
 at java.lang.Integer.parseInt(Unknown Source)
 at java.lang.Integer.parseInt(Unknown Source)
 at displayName.main(displayName.java:13)

• anonymous: Are u trying to print the ASCII numbers of the characters "Java"?
• Shantanu Nandan: @anonymous No i was trying to see what happens if i tries to convert an string name into an integer but now i know that its impossible. How can i get the ASCII value of "Java"?
• Louis Wasserman: @Shantanu: There is no way whatsoever to get the contents of the variable with the name corresponding to the contents of the string in Java.

Answer 1

You need to give it a string containing an integer :

String value="10";
int x=Integer.parseInt(value);

If you don't pass in a valid string it will throw an exception when trying to parse, which is what you're seeing.

Answer 2

That's because there's no integer in that string. You have to pass it a number as a string for that to work, otherwise there's no valid value to return.

Depending on your use case, it may be perfectly ok to catch that exception and use a default value in this case.

Answer 3

This is an example of how the String#parseInt is supposed to work

int see = Integer.parseInt("1234");

The string needs to represent a number.

---

Perhaps you're looking to get the ASCII value of the String?

String s = "Java";
byte[] bytes = s.getBytes("US-ASCII");

Answer 4

If you are looking for an Integer Object instead of the primitive type, you can use valueOf which returns

Integer i = Integer.valueOf("1234")

If you are new to Java try reading it here Difference between Integer and int.

Answer 5

Only numbers represented in the form of a String can be parsed using the Integer.parseInt() function. In other cases the NumberFormatException is thrown.

I would suggest Google and Wikipedia for simple things like these. They are a great source for learning and the first step towards solving simple doubts.

Hope this helped.