Debug assertion failed with std::erase

Question

I'm writing a program to parse a logfile, and decided to be as C++ about that as possible and I got hit with debug assertion for this line -

sLine.erase(remove_if(sLine.begin(), sLine.end(), isspace), sLine.end()); 

Which seems to because of a character of value -80 at like, 2000th line of the logfile.

So, I tried this

sLine.erase(remove_if(sLine.begin(), sLine.end(), [](char c) { return c >= -1 && c<=255; }), sLine.end());

But this code snippet gets stuck with no explanation.

So, finally I have three questions -

1. Why is that debug assertion is required?
2. What is the reason for the second code snippet to fail?
3. Any workarounds you could suggest?

Thanks for any help!

Answer 1

1. It is an assertion to test that the character argument is not out of range. The character '°' (-80) is not an ascii character so it is out of range.
2. I am not sure what you mean, this code snippet removes all ascii characters.

3. The following code will work if you just want to erase space characters

   sLine.erase(std::remove_if(sLine.begin(), sLine.end(), [](char c) { return (c == ' '); }), sLine.end());