regex: find integer but not float

Question

I want a regex pattern to find any integer in the string, but not float (with decimal point as "." or ",". So for string:

abc111.222dfg333hfg44.55

it should only find:

333

I created regex pattern:

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(?<!\\d[\\.,]|\\d)\\d+(?![\\.,]\\d+|\\d)

but it fails when using in C++ STL regex. It throws exception:

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Unhandled exception at at 0x76AF4598 in xxxxxx.exe: Microsoft C++ exception: std::regex_error at memory location 0x00C1F218.

but it works nice in C# Regex class

UPDATE:

My Code:

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smatch intMatch;
regex e1("(?<!\\d[\\.,]|\\d)\\d+(?![\\.,]\\d+|\\d)");
string s("111.222dfg333hfg44.55");
regex_search ( s, intMatch, e1 );

but it throws exception on the line:

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regex e1("(?<!\\d[\\.,]|\\d)\\d+(?![\\.,]\\d+|\\d)");

UPDATE 2:

Both answers are correct, but for C++ STL regex Toto one works better.

Answer 1

I'm not sure for C++ STL, but many regex flavors don't support variable length negative lookbehind.

In your case you can simply do:

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(?:^|[^.,\d])(\d+)(?:[^.,\d]|$)