Java vs. C#

Scope

Java
 
class A {}
class Test
{
    public static void main(String[] args) {
        String A = "hello, world";
        String s = A;                                
        Class t = new A().getClass();    
        System.out.println(s);  // writes "hello, world"
        System.out.println(t);  // writes "class A"
    }
}


class Test
{
    double x;
    void F(boolean b) {
        x = 1.0;
        if (b) {
            int x = 1;
        }
    }
}

C#
 
class A {}
class Test
{
    static void Main() {
        string A = "hello, world";
        string s = A;          // expression context
        Type t = typeof(A);    // type context
        Console.WriteLine(s);  // writes "hello, world"
        Console.WriteLine(t);  // writes "A"
    }
}


class Test
{
    double x;
    void F(bool b) {
        x = 1.0;
        if (b) {
            int x = 1;//error
        }
    }
}
compile-time error because x refers to 
different entities within the outer block.
The following is OK
class Test
{
    double x;
    void F(bool b) {
        if (b) {
            x = 1.0;
        }
        else {
            int x = 1;
        }
    }
}
because the name x is never used 
in the outer block