Rounded Corners
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self.UIElementName.layer.cornerRadius = 7.0; // vary this radius value to achieve suitable   corner

self.UIElementName.layer.borderWidth = 0.8f; //sets the border width of UIElement
self.UIElementName.layer.borderColor = [UIColor redColor].CGColor;



Square Corners
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self.UIElementName.layer.cornerRadius = 0.0; // sets the corner radius value to zero to get a square corner

Provide Square/Rounded corners for UIElements like UISegmentedControl, UIButton etc.

Use 'cornerradius' property for setting the type of corner.

Square & Rounded corner for UIElements

Objective C