Practice›Java Fundamentals›Module 3. Methods ›3.4 Scope and helpers

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3.4 Methods — local variables and scope

Lesson

Where a variable lives

A variable declared inside a method is local to that method: it exists only while the method runs, and it can't be seen from anywhere else. This is called its scope. Because of scope, two methods can each have a variable with the same name without interfering.

Worked example

void showX() {
    int x = 99;            // this x belongs to showX
    System.out.println(x);
}

int x = 5;                 // a different x, belongs to main
showX();                   // prints 99
System.out.println(x);     // prints 5 — main's x is untouched

▶ Try it: showX() has its own x = 99. Run this — the x in main stays 5, because the method's x is separate. Change the values and re-run.

public class Main {
    static void showX() {
        int x = 99;
        System.out.println(x);
    }
    public static void main(String[] args) {
        int x = 5;
        showX();
        System.out.println(x);
    }
}

Where can a variable declared inside a method be used?

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showX() declares its own int x = 99 and prints it. Type exactly what this prints:

int x = 5;
showX();
System.out.println(x);

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True or false?

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