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Parsing a string into integers using istringstream

I want to parse a string (actually a date [always in the format
'YYYYMMDD') into integer values like this:

void parseDate(const string&sdate, int& day, int& mon, int &year)
{
istringstream iss(sdate) ;
....
}

I can do this easily in C (using atoi etc), but i wanted not too sure
how in C++.

Nov 6 '06 #1
2 3436
Bit Byte wrote:
I want to parse a string (actually a date [always in the format
'YYYYMMDD') into integer values like this:

void parseDate(const string&sdate, int& day, int& mon, int &year)
{
istringstream iss(sdate) ;
....
}

I can do this easily in C (using atoi etc), but i wanted not too sure
how in C++.
First you need to convert "YYYYMMDD" into components.

std::string date = "20061113";

// Take care to assert here if the string is not long enough.
assert( date.size() == 8 );

std::string year( date.begin(), date.begin() + 4 );

std::string month( date.begin() + 4, date.begin() + 6 );

std::string day( date.begin() + 6, date.end() );

Then you can convert each component.
Nov 6 '06 #2
Gianni Mariani wrote:
Bit Byte wrote:
I want to parse a string (actually a date [always in the format
'YYYYMMDD') into integer values like this:

void parseDate(const string&sdate, int& day, int& mon, int &year)
{
istringstream iss(sdate) ;
....
}

I can do this easily in C (using atoi etc), but i wanted not too
sure how in C++.

First you need to convert "YYYYMMDD" into components.

std::string date = "20061113";

// Take care to assert here if the string is not long enough.
assert( date.size() == 8 );

std::string year( date.begin(), date.begin() + 4 );

std::string month( date.begin() + 4, date.begin() + 6 );

std::string day( date.begin() + 6, date.end() );

Then you can convert each component.

Yikes. This is a case where'd I'd just use old-style:
sscanf(sdate.c_ str(), "%4d%2d%2d" , &year, &mon, &day);
There's probably some Boost thing that does something similar, but I
don't know anything about that.


Brian
Nov 6 '06 #3

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