I have this simple function that, given a string str, if it is a number then return 'true' and overwrite the reference input num.
template <typename T>
bool toNumber(string str, T& num)
{
bool bRet = false;
if(str.length() > 0U)
{
if (str == "0")
{
num = static_cast<T>(0);
bRet = true;
}
else
{
std::stringstream ss;
ss << str;
ss >> num; // if str is not a number op>> it will assign 0 to num
if (num == static_cast<T>(0))
{
bRet = false;
}
else
{
bRet = true;
}
}
}
else
{
bRet = false;
}
return bRet;
}
So I expect that:
int x, y;
toNumber("90", x); // return true and x is 90
toNumber("New York", y); // return false and let y unasigned.
On my machine, both debug and release configurations works fine, but on the server, only with the debug configuration, in calls like toNumber("New York", y) the 'ss >> num' fails to recognize that str is a string.
I checked the project configuration, but they are the same for both machines (the server is a svn-checkout of my local vs-2015 project).
I have literally no idea on how to solve the problem. Can anyone help me with this?
Your code is made too complicated, you can simplify it to this:
template <typename T>
bool toNumber(std::string str, T& num)
{
return !!(std::istringstream { std::move(str) } >> num);
}
https://godbolt.org/z/Pq5xGdof5
Ok I've missed that you wish to avoid zero assignment in case of failure (what streams do by default):
template <typename T>
bool toNumber(std::string str, T& num)
{
T tmp;
std::istringstream stream{ std::move(str) };
if (stream >> tmp) {
num = tmp;
}
return !!stream;
}