How to Handle Line Numbers and Text in a Menu-Driven String Editor?

[Trista]

I'm having some trouble writing the menu part of this program. Right now, I have everything in main() just for ease of compiling. The file is attached.

There are 5 basic commands: I, D, L, A, E
I = insert a line, D = Delete a line, L = list a line, A = Append to end of list,
E = exit.
Thats easy. The hard part is that a line number may follow the command.
I 5 means insert a string that follows before line 5.
D 5-13 means delete lines 5 through 13.
L 3 - 7 means list lines 3 - 7.

If text follows the numbers then it is considered a string and not a command.

I bring in the line using cin.getline(newString, 255, \n). newString is of type char. I'm not sure what to do with the loop to determine if there are numbers, then if the line is more than one digit ( 20 ) how do I push them together to represent the line number, AND then if there is letters after the numbers its a string... its all so confusing!

Please help me get through this!

thank you so much for your help!

Trista

 

[Aaron Bex]

One way to approach this is to use a loop and the cin.get() function. Inside the loop, you can read in each character of the command one by one. You can then determine if the current character is a number, letter, space, or something else. Depending on what it is, you can take the appropriate action. For example, if you encounter a number, you can store it in a variable until you encounter a non-number character. This way, you can build up the line number that the user is entering. If you encounter a letter, you can break out of the loop and use the string that has been built up. This can be done with a simple if-else statement.

 

[ravenprp]

Hello Trista,

I understand that you are having trouble writing the menu part of your string editor program. It can be overwhelming when there are multiple conditions and variables to consider, but don't worry, I am here to help.

Firstly, let's break down the 5 basic commands: I, D, L, A, and E.

- I: This command is used to insert a line. It can be followed by a line number, which indicates where the new line should be inserted.
- D: This command is used to delete a line. It can be followed by a line number or a range of line numbers to be deleted.
- L: This command is used to list a line. It can be followed by a line number or a range of line numbers to be listed.
- A: This command is used to append a line to the end of the list.
- E: This command is used to exit the program.

Now, let's focus on how to handle the line numbers and strings.

When a user enters a command followed by a line number, we need to separate the command and the line number. One way to do this is by using the getline() function and specifying a delimiter, in this case, a space. This will allow you to store the command in one variable and the line number in another variable.

Next, we need to check if the line number is a single digit or multiple digits. One way to do this is by using the isdigit() function, which checks if a character is a digit or not. If the line number is a single digit, you can simply convert it to an integer using the atoi() function. If the line number is multiple digits, you can use a loop to read each character and store them in a string. Once all the digits are read, you can then convert the string to an integer using the stoi() function.

Now, if there are letters after the numbers, it means that it is a string and not a line number. In this case, you can use the getline() function again to read the string and store it in a variable.

I hope this helps you understand how to handle the line numbers and strings in your menu-driven string editor program. Remember to break down the problem into smaller parts and take it one step at a time. If you need further assistance, don't hesitate to reach out for help. Good luck!