How can I replace tokens in a string

Question

0.00/5 (No votes)

See more:

I'm writing a program on Windows in regular C using Visual Studio 2017.

I'm reading a file one line at a time into a char[1024] variable and then writing it back out to another file.

The line can contain none, one, or several occurrences of: @{varname}

I need to replace @{varname} in the output file with a value from a database that I lookup using the value between the brackets.

The value from the database could be larger than 1024 so I need to write the portion of the line prior to the @ to the output file, then write the value from the database, then write the portion of the line after the }.

Conceptually it is like a mail merge. I just need some help figuring out the best way to parse out the parts of the line. I control the format of the input file so could change the characters around the variable names if needed.

What I have tried:

I've tried several things including strtok and various str**** runtime functions.

Posted 10-Jan-20 18:00pm

Roland M Smith

Updated 10-Jan-20 21:20pm

Add a Solution

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

OriginalGriff · Accepted Answer · 2020-01-10T21:21:00

Start by setting up an output line to copy into.
Then process the input line:

1) Create a variable called foundAt, set it to false.
2) Loop through input
2.1) If  foundAt is true, check if this is a '{'.
2.1.1) If it is, loop though the input to find the matching '}'. This give you the name, so you can search the db, and copy the replacement string to the output. Set foundAt to false and use <code>continue</code> to skip the rest of your loop body.
2.1.2) If it isn't, copy an '@' to the output and clear foundAt
2.2 Is the input character an '@'?
2.2.1) If it is, set foundAt to true;
2.2.2) Otherwise, copy the character from the input to the output
3) Move on to the next input character and loop round again until all inputs are processed.

Make sense?