if there is black parent with two red childrenand you place the red arrow on the parent by clicking on the node with the mousethen when you press the flip button the parent will become red and the children will become black that isthe colors are flipped between the parent and children you'll learn later why this is desirable thing to do if you try to flip the rootit will remain blackso as not to violate rule but its children will change from red to black the rol button this button carries out left rotation to rotate group of nodesfirst single-click the mouse to position the arrow at the topmost node of the group to be rotated for left rotationthe top node must have right child then click the button we'll examine rotations in detail later the ror button this button performs right rotation position the arrow on the top node to be rotatedmaking sure it has left childthen click the button the / button the / button changes red node to blackor black node to red single-click the mouse to position the red arrow on the nodeand then push the button (this button changes the color of single nodedon' confuse it with the flip buttonwhich changes three nodes at once text messages messages in the text box below the buttons tell you whether the tree is red-black correct the tree is red-black correct if it adheres to rules to listed previously if it' not correctyou'll see messages advising which rule is being violated in some cases the red arrow will point to where the violation occurred where' the find buttonin red-black treesa search routine operates exactly as it did in the ordinary binary search trees described in the last it starts at the rootandat each node it encounters (the current node)it decides whether to go to the left or right child by comparing the key of the current node with the search key we don' include find button in the rbtree applet because you already understand this process and our attention will be on manipulating the red-black aspects of the tree experimenting now that you're familiar with the rbtree buttonslet' do some simple experiments to get feel for what the applet does the idea here is to learn to manipulate the applet' controls later you'll use these skills to balance the tree experiment press start to clear any extra nodes you'll be left with the root nodewhich always has