Exer17_14.cpp

#include <iostream>
#include <string>
#include <regex>
using std::cout;
using std::endl;
using std::string;
using std::regex;
using std::smatch;
using std::regex_error;
int main()
{
    // [] mismatch
    try {
        regex r("[[:alnum]+\\.(cpp|cxx|cc)$", regex::icase);
    } catch (regex_error e)
    { cout << e.what() << "\ncode: " << e.code() << endl; }
    // () mismatch
    try {
        regex r("[[:alnum]]+\\.cpp|cxx|cc)$", regex::icase);
    } catch (regex_error e)
    { cout << e.what() << "\ncode: " << e.code() << endl; }
    // {} mismatch
    try {
        regex r("[[:alnum]]{1-2\\.(cpp|cxx|cc)$", regex::icase);
    } catch (regex_error e)
    { cout << e.what() << "\ncode: " << e.code() << endl; }
    // repetition character not preceded by a valid RE
    try {
        regex r("+\\.(cpp|cxx|cc)$", regex::icase);
    } catch (regex_error e)
    { cout << e.what() << "\ncode: " << e.code() << endl; }
    // invalid range in {}
    try {
        regex r("[[:alnum]]{a-x}+\\.(cpp|cxx|cc)$", regex::icase);
    } catch (regex_error e)
    { cout << e.what() << "\ncode: " << e.code() << endl; }
    // invalid character range
    try {
        regex r("[z-a]+\\.(cpp|cxx|cc)$", regex::icase);
    } catch (regex_error e)
    { cout << e.what() << "\ncode: " << e.code() << endl; }
    return 0;
}
// ******result of clang++ and g++******
// regex_error
// code: 1
// regex_error
// code: 1
// regex_error
// code: 1
// regex_error
// code: 5
// regex_error
// code: 1
// regex_error
// code: 8

// ******result of cl******
// regex_error(error_ctype): The expression contained an invalid character class
// name.
// code: 1
// regex_error(error_ctype): The expression contained an invalid character class
// name.
// code: 1
// regex_error(error_ctype): The expression contained an invalid character class
// name.
// code: 1
// regex_error(error_badrepeat): One of *?+{ was not preceded by a valid regular
// expression.
// code: 10
// regex_error(error_ctype): The expression contained an invalid character class
// name.
// code: 1
// regex_error(error_range): The expression contained an invalid character range,
// such as [b-a] in most encodings.
// code: 8