I have declared a variable in .h:

```
@property (nonatomic, retain) NSString *var;

```

When i call a property variable using:

```
 _var = sumthing;

```

the app crashes and when i call it as:

```
 self.var = sumthing;

```

it works well.

Is there any difference in these two scenarios?

NOTE: I have not used `@synthesize` as it is not required to write this specifically.