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use:

Assuming the list is in column A, you can try

Try

One way would be as follows:

First, just separate the input-gathering from the counting, so we'll just gather input in this step:

the problem is that in cost_total you are using cost_tax to calculate the total value, but cost_tax is a string and not a float. Your program will work if you change this line by:

Your winpercent isn't numeric (notice the quotes around the numbers and .s as separators) so we'll first address that, then we'll create a new variable based on the values:

• Right click on your tableadapter (on the header, not the Fill command), and choose Configure

• Click Advanced Options and verify that "Generate I/U/D" is ticked

When this isn't ticked, the resulting TA doesn't have any DML statements built:

If your SELECT statement doesn't select the column that is set as the primary key in the database, then this Generate IUD tickbox may be greyed out, or it will be ticked but the DML statements won't generate. Pay attention to the final page of the wizard. Here is what happened when I made a table "Other" that had no primary key:

INSERT generates, because it's easy to generate an insert on a keyless table, but update and delete cannot be generated

If you don't select the PK column you get a warning:

It's important that your DB tables have a PK; it's not the same thing to declare some datacolumns of a datatable in a dataset to be a primary key. A Dataset is not a database; it may have more or fewer tables/columns and the presentation and datatypes of row data do not have to match the DB. I can see that your dataset screenshot shows some tables have PKs declared in the DataSet side, but this is not a statement that they are definitely PKs on the DB side

Feel free to delete the DataTable; it will delete the TableAdapter too. You can then recreate that one TA by right click, new, tableadapter.. SELECT * FROM table

If you hadn't already realized, remember that you can (and should) declare more queries per tableadapter than just keeping with the basic Fill, which appears to be a SELECT * FROM without a WHERE clause in your case. Personally I always make my first query SELECT * FROM table WHERE id = @id because it's really rare that you want to download a whole table.. You can leave the default as a WHEREless query, but consider adding others, such as SELECT * FROM Twix WHERE Location = @location and naming the query FillByLocation. In code you can then fill just the locations you want, rather than downloading 10000 Twixes into the app just to show some of them (with a rowfilter, i guess)

What you would like to do is:

• Read the product content of the vending machine from a file
• Modify data somehow
• Write the product content of the vending machine to a file

How does modify somehow work? As you cannot change files online with arbitrary new data, you need to do like this:

Read file into memory --> operate on data in memory --> Save modified data in file

For the above there are 2 approaches.

• Open file --> Read data --> Close file --> Modfiy data in memory --> Open file for output by overwrite original file --> Save Data --> Close file

Or, a little bit safer:

• Open file --> Read data --> Close file --> Modfiy data in memory --> Open temporary file for output --> Save Data in temporary file --> Close temporary file --> If everything OK, delete original file --> rename temporary file to orignial file name

But the key is, to work on the data in memory.

You can also create "load" and "save" fucntions. So, at any time, after changing data in memory, you could "save" the modified data. With one of the above described methods.

Or, you could "load" your data in a constructor and "save" it in a destructor. Everything would then work automatically.

Regarding the "load" function. You need to read the source file line by line and then split the line into your needed data members. I have answered a question here, which describes 4 different methods on how to split a line. In the below given example, I use a std::regex based solution using std::regex_match. This will ensure that the data is in the expected format.

Please note that you should also overwrite the extractor and inserter operators >> and << for easier working with streams.

And last but not least, everything should be encapsulated in classes.

Please see a working and tested example code for a partial implemented vending machine functionality. In this code I am using C++17 features, like if with initializer. So, If you want to compile, then please enable C++17 for your compiler.

Additionally, this is just some code to illustrate the explanations above. There are 1 million solutions. In the end you need to come up with sometthing fitting the requirements.