how can we record the output of the debugger (including data type values)
we've identified a "trace.txt" exists that logs all information dealing with the ROBOTC's debugging process
where can we find it?

platform: windows 7
robotc version: 3.5.4

You can use the writeDebugStream and writeDebugStreamLine commands (found here on our wiki) to write values to the Debug Stream debugger window; you can write messages and/or sensor values directly to the debugger window. For example:



This program has a Sonar sensor on port 1 (aptly named 'sonar'). It also creates an integer called 'foo' that we will use as a placeholder for the elapsed time.

The first line of code, 'clearDebugStream();' clears any old values from the Debug Stream debugger window. The second line, ClearTimer(T1) clears out the timer we will be using and the while(true) loop keeps the program running indefinitely. The integer foo is then assigned the value of the timer T1, divided by 10 to give whole numbers.

The writeDebugStreamLine tells the program to make a new line that contains the text "The sonar value at", a decimal value, "seconds is ", and another decimal value (the %d means 'decimal value'; %f, for instance, stands for float. There is a full listing of the supported types on our wiki.) After the text are the parameters for the first %d value and the second %d value; in this case the variable 'foo' (which holds the value of the T1 timer) and the value of the Sonar sensor. We then wait for 1 second and loop through again.

The result result, which appears in the Debug Stream window, looks like this:

You can modify the code or use the writeDebugStream commands in custom code to display whatever you need it to. You can then copy and paste the information to another document (an Excel spreadsheet, for instance) and save it locally.

cool.....

Is there someone who could explain in more detail for me?

I don't get it.

The debug stream is a small window that appears while you are debugging a program in RobotC (after you've compiled/downloaded and started the program). You can include this code ...

... to automatically display it.

The program sends formatted strings to the debug stream, which acts like a console output, or the NXT display screen. Using the writeDebugStream and writeDebugStreamLine functions, the program can display text in a window on the computer screen that may reflect sensor readings, joystick values, or any other variables the robot is dealing with. As JohnWatson said, string formatting allows you to insert variables and other non-constant elements into the display text.



In this code, the program replaces '%i' with the argument given, 5 (so it would print "I have 5 burritos"). '%i' refers to integers, '%f' to floating point decimal numbers, '%s' to strings, etc. There's a complete list here.