The Big Programming Thread - Page 766

public class Box {

    private int id;
    private String name;
    
    private static int boxId;

    static {
        boxId = 0;
    }

    public Box(String name) {
        id = Box.getBoxId();
        this.name = name;
    }
        
    public static int getBoxId() {
        int ret = Box.boxId;
        boxId++;
        return ret;
    }
    
    public void setId(int id) {
        this.id = id;
    }
}

$i = 7;

foreach ($somevar as $i) {
    // do stuff
    // $i declared before loop is overriden with each iteration
}

// $i is now whatever the last element of the iterable $somevar was

int fizz, bar;

public void foo(int bar) {
  this.bar = bar; //fine, no warning
  bar = bar; //warning (assigning bar to itself)
  this.fizz = fizz; //warning (fizz is only in the outer scope, thus self assignment again.)
}

int fizz, bar;

public void foo(int bar) { // this is where it could show a warning that bar is shadowing this.bar

    int fizz; // this is where it could show a warning that fizz is shadowing this.fizz

    // ... enough code to make you forget the line above ...

    fizz = 5; // here you could mean to assign to this.fizz, introducing a bug

    // and if we have some slightly more complex code with say loops, you might not even get a 
    // "value assigned to variable is never used" warning
}

int fizz, bar;

public void foo(int bar) { // this is where it could show a warning that bar is shadowing this.bar

    int fizz; // this is where it could show a warning that fizz is shadowing this.fizz

    // ... enough code to make you forget the line above ...

    fizz = 5; // here you could mean to assign to this.fizz, introducing a bug

    // and if we have some slightly more complex code with say loops, you might not even get a 
    // "value assigned to variable is never used" warning
}

def method(self, bar):
   ... code here ...