I want to send a string to a method and change the string there. The method should return void. Example:
String s = "Hello";
ChangeString(s);
String res = s;
//res = "HelloWorld"
-------------------------------------------
private void ChageString(String s){
s = s + "World";
}
How can I do it in Java? Can it be done without adding another class?
Thanks! PB
Nope, can't be done while returning void.
Java passes parameters by value. Strings are immutable, so you can't change its value. You're out of luck.
You can do this:
private String changeString(String original) {
return original + " World";
}
You could wrap up your string in an object:
public class StringWrapper {
String _str;
public StringWrapper(String str) { set(str); }
public void set(String str) { _str = str; }
public String toString() { return _str; }
}
Allowing you to do:
StringWrapper s = new StringWrapper("Hello");
ChangeString(s);
String res = s + "";
//res = "HelloWorld"
private void ChageString(StringWrapper s) {
s.set(s + "World");
}
Use the StringBuffer/StringBuilder to change the string. Strings in java are immutable, this means that once they are assigned a value, they cannot be changed, the code that seems to be changing the string actually makes a new object. Here's something on string buffer, hope it helps. :)