Can't understand the log levels exercise C++

Programming C++
1

My thought process: I need to make a sub string out of a given string and return it. I find the first index for substr() with find().

Here is my code:

#include <string>

namespace log_line {
std::string message(std::string line) {
    return line.substr(line.find("Invalid"));
}

std::string log_level(std::string line) {
    // return the log level
    return line.substr(line.find("ERROR"), 5);
}

std::string reformat(std::string line) {
    // return the reformatted message
    std::string first{line.substr(line.find("Operation"))};
    std::string second{line.substr(line.find("INFO"), 4)};
    std::string final{first + " (" + second + ")"};
    return final;
}
}  // namespace log_line

This is the error:

make[2]: *** [CMakeFiles/test_log-levels.dir/build.make:70: CMakeFiles/test_log-levels] Error 8
make[1]: *** [CMakeFiles/Makefile2:111: CMakeFiles/test_log-levels.dir/all] Error 2
make: *** [Makefile:91: all] Error 2

I just don’t understand what the error means. Where do I need to look? I checked out the std::string docs on learncpp, I read about std::basic_string, I listened about namespaces from Bro Code.

I also tried to do it locally on my machine and it works.

2

Please post code as a fenced code block, not as a screenshot.
Not everybody can read images and text is easy to copy for anybody who wants to reproduce the error.

This kind of error without a helpful error message is often caused by an exception where the tests do not expect one.

In this case std::string::substr() throws a std::out_of_range exception if the first argument (the index where the substring begins) is greater than the size of the string.
That happens when std::string::find() does not find the searched-for string and returns std::string::npos which is a very large integer.

The lines 5, 10, 15, and 16 search for the strings "Invalid", "ERROR", "Operation", and "INFO". Are you sure that these strings are guaranteed to be part of the line? If not what other separator could you use?