What should the level-two program look like?

• The level-two program needs documentation for the main program, for the functions called by the main program (they are called level-two functions), and for the functions called by the level-two functions (they are called level-three functions.)
  
  
• The documentation for every function must tell what the function will do when it is completed. (Normally you don't write documentation to tell what a stub function does.)
  
  
• In the level-two program you need to finish the code for the main function and all the level-two functions.
  
  
• In the level-two program you need to have stubs for all the level-three functions.
  
  
• If you follow my suggested design the main program will have some declarations of variables, perhaps some function prototypes, perhaps an initial call to askPermission, and a loop containing calls to getParams, getImage, doTileJob, and askPermission.
  
  
• In your level-two program you can probably put versions of askPermission, and getParams that don't make calls to any level-three functions (except 'built-in' functions that you don't need to write).
  
  
• Depending on how you want to design the program, you may want getImage to call a level-three function that you write. On the other hand you may not want to do that.
  
  
• I think doTileJob really has to call a level-three function to do most of the work. I think doTileJob is bound to be too long and complicated-looking if you try to write it without a lot of reliance on a level-three function.
  
  
• getImage and doTileJob are both functions that could be written with the basic structure of a for-loop.
  
  
  1. Basically, getImage can:
     • open the file
     • get the height and width of the image,
     • then perform a loop: "For each row index i from 0 to heightOfFileImage-1 move to the beginning of the next line of the image file and copy the characters on that line into row i of the buffer array," and then
     • close the file
     
     The function that copies the next line of the file into the buffer can be a stub in your level-two program. You can put off figuring out how to do that part of the problem until you start work on the level three program.
     
     
  2. The basic structure of doTileJob could be "For each row index i from 0 to numberOfRowsInTheTiling, make a row of numberOfColumnsInTheTiling 'tiles' across the standard input (you have to do it by copying characters out of the buffer array). The function that makes the row of tiles can be a stub in your level-two program. You can put off figuring out how to do that part of the problem until you start work on the level three program.