I want to fill a path with red. This is my code:

```
CGFloat red[4] = {1.0f, 0.0f, 0.0f, 1.0f};
CGContextBeginPath(c);
CGContextSetStrokeColor(c, red);
CGContextSetFillColorWithColor(c, [UIColor whiteColor].CGColor);
CGContextMoveToPoint(c, 10, 10);
CGContextAddLineToPoint(c, 20, 20);
CGContextAddLineToPoint(c, 20, 40);
CGContextAddLineToPoint(c, 40, 20);
CGContextAddLineToPoint(c, 10, 10);
CGContextStrokePath(c);
CGContextFillPath(c);

```

I know that I have to use `CGContextSetFillColor()` and `CGContextFillPath()`, but it's not working.

How can I do this correctly?