a question about method local variables

[amalip epa]

k&b says always must be initialized before you attempt to use them. but i can't understand the answer of the below question

public class Test{
publis statis void main(String args[]){
int age;
age = age + 1;
System.out.println("The age is" + age);
}}

the answer was Doesn't compile
and i thought it wud print 1

[Ernest Friedman-Hill]

On the fourth line, the value of "age" is read, 1 is added to that value, and the result stored back in "age". But when "age" is declared on the third line, no value is assigned to it. Therefore, it is uninitialized, and the code on the fourth line that tries to read the value won't compile.

[Alan Jump]

public class Test{
public static void main(String args[]){
int age;
age = age + 1;
System.out.println("The age is" + age);
}}

This won't compile because age was never initialized, only declared. If you try to make use of a declared variable before it's initialized you'll get a compile-time error.

(Edited to correct typo in code)

[ May 26, 2005: Message edited by: Alan Jump ]
[ May 26, 2005: Message edited by: Alan Jump ]

[Nik Raut]

And what about the default initialization to 0 for integers?

[Alan Jump]

age was declared inside a method (i.e. local variable), so it doesn't automatically get a default value.