How to view variables during program execution

I am writing a relatively simple C program in Visual C++, and have two global variables which I would like to know the values of as the program开发者_如何学编程 runs. The values don't change once they are assigned, but my programming ability is not enough to be able to quickly construct a text box that displays the values (I'm working in Win32) so am looking for a quick routine that can perhaps export the values to a text file so I can look at them and check they are what they ought to be. Values are 'double'.

I was under the impression that this was the purpose of the debugger, but for me the debugger doesn't run as the 'file not found' is always the case.

Any ideas how I can easily check the value of a global variable (double) in a Win32 app?

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Get the debugger working. You should maybe post another question with information about why it won't work - with as much info as possible.

Once you have done that, set a breakpoint, and under Visual C++ (I just tried with 2010), hover over the variable name.

You could also use the watch window to enter expressions and track their values.

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If your debugger isn't working try using printf statements wherever the program iterates. Sometimes this can be a useful way of watching a variable without having to step into it.

If however you wish to run through the program in debug mode set a breakpoint as suggested (in VS2010 you can right click on the line you want to set a breakpoint on).

Then you just need to go to Toolbars -> Debug Toolbar.

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I usually like to put #ifdef _DEBUG (or write an appropriate macro or even extra code) to do the printing, and send to the output everything that can help me tracking what the program's doing. Since your variables are never changing, I would do so. However, flooding the console with lots of values is bad imo, and in such cases I would rely on assertions and the debugger - you should really see why it's not working. I've done enough Python and Ruby to tell you that debugging a complex program when all you have is a printf, although doable, is extremely frustrating and takes way longer than what it should.

Finally, since you mention your data type is double (please make sure you have a good reason for not using floats instead), in case you add some assertion, remember that == is to be avoided unless you know 100% that == is what you really really want (which is unlikely if your data comes from calculations).