Does std::string class handle clean up if the assignment operator fails due to length_error or bad_alloc? Does it give me back my intact string I provided?
UPDATE: SOLVED: YES OPERATOR= IS SAFE PER MY REQUIREMENTS. THE CODE BELOW ADDS NO VALUE TO EXCEPTION SAFETY
given this reference from https://cplusplus.com/reference/string/string/operator=/ about exceptions
if the resulting string length would exceed the max_size, a length_error exception is thrown. A bad_alloc exception is thrown if the function needs to allocate storage and fails.
The explanation below is assuming std::string class doesn't fix any assignment that was done.
I figured if I assigned *this ("num" below) to a temp I could save any damage done to *this if the line num = other.num; below failed. The reason I am not sure if this is futile is because this snippet num = temp;, The fact I do not check this for success could be a failure. Is my code futile? Is there a standard way to handle this that I am missing?
const BigInt
&BigInt::operator=(const BigInt &other)
{
string temp = num; // using string operator=
if (temp.compare(num) == 0)
{
try
{
num = other.num;
}
catch(...)
{
num = temp;
throw;
}
return *this;
}
return *this;
}
RESOURCES PER ANSWERS GIVEN:
string operator= https://en.cppreference.com/w/cpp/string/basic_string/operator%3D
> If an exception is thrown for any reason, this function has no effect (strong exception guarantee). (since C++11)
