GUI_5

代码说明：

  function [] = GUI_5() Demonstrate how to use a pushbutton to delete bits of string and how to let the user know that their actions are futile. After the string is deleted completely, the user is informed that there is nothing left to delete if the delete button is pressed again. A color change accompanies this announcement. Suggested exercise: Add a counter to S that starts incrementing when the warning is given. If the user clicks again, close the GUI. button is pushed, each line of text from the editbox is placed as an entry into the listbox. Notice the difference between how a wrapped line is treated and a returned line is treated in the lisbox.