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SENSING BLOCKS

                 The blocks in the Sensing category help the selected sprite to detect the presence of other
                 sprites or other elements on the stage including the edges of the stage. The blocks in the Sensing
                 category are colour coded as light blue.

                 Some of the blocks included in the Sensing category are shown along
                 side.
                 The Table below shows some  important sensing blocks  and their
                 functions.

                                               Becomes true  when  the  sprite  touches
                                               the mouse pointer  or  the edge  of the

                                               stage (defined by clicking on the drop-
                                               down arrow)
                                               Becomes true when the sprite touches a
                                               defined colour
                                               Becomes true when color1 touches color2



                                               Becomes true  when  a  defined  key  is
                                               pressed on the keyboard

                                               Asks a question from the user and waits
                                               for the answer                                      Sensing block
                                               Stores the answer or input given by the
                                               user


                 Let us develop a simple program where the cat sprite moves
                 towards a basketball when right arrow key is pressed. The code
                 for the cat sprite can be similar to this.


                     STORING USER INPUT


                 The program can also be developed to take input from the user. Earlier,
                 we developed a program to divide 12 by 5. Scratch gives an option to
                 take input from the user also.
                 To develop a program to divide two numbers and find the quotient,
                 define the script of the sprite similar to the one given alongside.

                 When the program is run, a small text input box opens at the bottom
                 of the stage. Type the value of the variable and press Enter key or
                 click on the tick mark symbol on the right side of the text box.


                                                                                            Script to divide two numbers

                                                                                               Game on Scratch       77
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