Debug assertion failed! How to solve the problem?

One day the debugger suddenly jumps out of the following error:

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Microsoft Visual C + + Debug Library
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Debug Assertion failed!


program:i:\ Guangdong unicom \ Ministry of the background program \debug\batchsave.exe
File:f:\dd\vctools\crt_bld\self_x86\crt\src\strtol.c
line:94


Expression:nptr!= NULL


For information on how your the program can cause a assertion
Failure, the Visual C + + documentation on asserts.


(Press Retry to debug the application)
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Abort (A) retry (R) ignore (I)
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Tracking Solution:

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1, press F5 to run your program
2, in case of error, select "Retry"
3. Press Alt+7 to pull up the call Stack window
4, double click from the last one of their own defined function, the system will automatically display the function of the file, at this time the program is suspended at the cursor. In general, mistakes are in the vicinity. You can confirm it by looking at the value of the variable.

A good way to debug.