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    CONDITIONAL STATEMENTS

                  Many times, you have to do a task which is dependent on some condition. For example, you
                  have to make mango shake. There are two conditions:

                  a.   Go to the refrigerator and check if there are mangoes. If mangoes are there, then you will
                      make mango shake.

                  b.   If mangoes are not there, you will make cold coffee.

                    Here the condition is the availability of mango.
                    We can also write this in two ways:
                     1. if                                               2.  if
                            mango is available                                       mango is available

                       then                                                   then
                            make the mango shake                                     make the mango shake
                                                                              else

                                                                                     make cold coffee

                     In such situations, we use conditional blocks. Scratch has two conditional blocks. They are:

                      If,then block: In this block if the condition is true, the blocks inside conditional block will
                     run. If the condition is false, the blocks inside conditional block will not run. Only the blocks
                     outside the conditional block will run.

                      If,then,..else block: In this block if the condition is true, the blocks
                     inside then condition will run. If the condition is false, the blocks
                     inside else condition will run.

                  You can also use the forever and repeat blocks with these blocks.
                  Let us make a small script.
                    Change the sprite to butterfly and change the backdrop to flowers.

                  Drag the Event block, when Green Flag clicked to the script area.
                  Drag the control block, forever to the script area and put it to the
                  Green Flag block. Drag the move block and put it inside the forever
                  block. Now, drag the if on edge, bounce block and put it inside the
                  forever block.

                                             Now, put the control block if, then inside the
                                             forever block  and  snap  the  sensing  block,
                                             touching color  in the hexagon of the if loop.

                                             The butterfly changes colour and size when
                                             it touches the colours selected in the touch
                                             block.

                  Similarly, you  can  create scripts  with  two  sprites and  they  change
                  colour when they touch each other.

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