Back to [CEReAL group] / [CLUE project]
NED
Beta
Novice Errors Detection for C Programs

Start using NED now!

By using NED, you certify that you read, understood & agreed to the terms of usage.

Option #1 - Select files to upload

Use the file-browser below to select, one by one, all the .c or .h files in your project. Leave empty browsers if you do not need to analyze this many files. When you use the "Analyze" button, your files will be uploaded & analyzed. A new tab will open in your browser with a full report on possible errors.


Option #2 - Drag and Drop the files to upload

You might alternatively select a bunch of files in your file browser then drag and drop them here...

Drop Files Here to Upload

Option #3 - Upload a zip of your projet

You may alternatively zip your entire project folder then select the resulting zip file to upload


Things to keep in mind

This web app has been developed for Firefox. You may download a portable firefox version if you do not want to fully install it on your system. It should work on other standards-adhering browsing

Keep in mind these are potential errors, things you should take another look at in order to make sure they are not mistakes. Unfortunately, there is so much a program may do to understand another program.

Do not hesitate to drop us feedback, see about details here. If you want to learn a bit more about this project read here

Search through our tutorials

This table lists all our tutorials so you may peruse through them. The number of views for each is also displayed; this is not the number of times the error occured in an uploaded set of files but rather the number of times a user clicked on the messages hyperlinked to this tutorial in order to read it.

Similarly, the usefulness is based on the number of users who clicked yes at the bottom of a tutorial page. The uselessness is based on the number of those who clicked no.

The Freq. value represents how often the errors or warnings which the tutorial explains have been found during uploaded files analysis. It is a good estimate of the frequency of the underlying bugs among all NED users

Do not hesitate to use the mini-survey feature which you will find in the last section of each tutorial page. It helps identify both the tutorials in need of improvement but also those we should use as models.

Name From Type Details Views Useful Useless Freq.
Unused VariablesCompilerWarningVariable declared, maybe even assigned, but never used385011606
Undeclared VariablesCompilerErrorUndeclared variable used37722414
Undefined ReferencesLinkerErrorUndefined reference to function or variable37811
Missing Return StatementAnalyzerWarningFunction is missing return statement36410109
Missing Array SizeCompilerErrorThe size of an array is not specified3531166
Empty BlockAnalyzerWarningYour program features an empty block36312213
Single Quote StringCompilerWarningUsing single quote as string delimiter3735398
Unexpected Break StatementAnalyzerWarningUnexpected break statement3650062
Missing break statementAnalyzerWarningMissing break statement35983
Unreachable StatementsAnalyzerWarningUnreachable statements37717132
= vs. ==CompilerWarningAssignment used in Boolean expression41321389
Unary OPs in Larger ExprAnalyzerWarningUnary operators used in larger expression37400358
Bitwise vs. LogicalAnalyzerWarningUse of bitwise binary operator instead of logical operator37201284
Expected SemicolonCompilerErrorExpected semi-colon3622168
Dangling PointerAnalyzerWarningDangling pointer35831123
Dereferencing NULLAnalyzerWarningDereferencing NULL pointer3842562
Dereferencing Incomplete TypesCompilerErrorDereferencing a pointer to an incomplete data type36033420
Multi-free on same memory blockAnalyzerWarningFreeing multiple times the same memory block3740164
Memory LeakAnalyzerWarningMemory leak37604178
Freeing unallocated pointerAnalyzerWarningFreeing non-allocated memory36522138
sizeof on PointerAnalyzerWarningUsing sizeof operator on pointer36612
Uninitialized PointersAnalyzerWarningUnitialized pointer33816
Discarding Ptrs QualifiersCompilerWarningAssignment or cast discards pointers qualifier37011
Unchecked MallocAnalyzerWarningReturn value from malloc or similar function is not checked36501351
Unexpected EOFCompilerErrorUnexpected EOF3693374
Unterminated literalCompilerErrorMissing end-delimiter for character or string literal35321456
Useless ValueAnalyzerWarningStatement results in a value which is never used37031652
Void not IgnoredCompilerErrorAttempting to use a void returned value3840682
Missing EOF NewlineCompilerWarningMissing newline at end of file35630
Multiple Unary Ops on VariableCompilerWarningUsing multiple unary operators on same variable in a single expression37903215
Empty Char LiteralCompilerErrorEmpty character literal3483273
Using Uninitialized VariableCompilerWarningVariable not initialized3692277
Forward Parameter DeclarationCompilerErrorParameter has a forward-declaration373031640
Unexpected Data TypesCompilerErrorUnexpected multiple data types where one is expected37803195
Unexpected Arguments NumberCompilerErrorUnexpected number of arguments35610138
Mismatch numbers for args / specifiersCompilerWarningThere is a mismatch between the number of format specifiers used in a printf or scanf, and their arguments35221286
Mismatch types for args / specifiersCompilerWarningThere is a mismatch between the data type of format specifiers used in a printf or scanf, and the data type of the corresponding argument35022572
Using unknwon struct fieldCompilerErrorUnknown struct field36920134
Parameters Storage ClassCompilerErrorStorage class specified for parameter3482065
Shadowed IdentifierAnalyzerWarningShadowing variable already in scope3492146
Argument ConversionCompilerWarningArguments data type is converted35620445
Modifying ParametersAnalyzerWarningFormal parameters are assigned inside function35620135
Assign Integer to PointerCompilerWarningAssigning non-NULL constant to Pointer37201216
Mixed Pointers DeclarationsAnalyzerWarningDeclaring variables in one statement with pointer and non-pointer data types35520
Missing Function DeclarationCompilerWarningMissing function declaration36131
Function should not be exportedAnalyzerWarningFunction is not static to its file, yet unused in other files37130919
Off by oneAnalyzerWarningA loop might be off by one in its number of iteration; e.g. start at 0 instead of 13360038
Formatting String MismatchAnalyzerWarningA printf or scanf is using a formatting string with conversion specifiers unrelated to the parameters35901
Assign pointer to integerAnalyzerWarningAssigning memory address to variable expecting integer36500162
29400
33500
32800
30700
32800
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100