reformatting a string - help please

[Dj Frenzy]

Hi,
this should be a pretty easy question for the advanced people on
here. Basically , I have two strings:

string transDate = "20030901";
string transTime = "1200";

I want to know the best way to reformat them into a more recognisable
format so that:

transDate = "01/09/2003";
transTime = "12:00";

At the moment I just have a function like this:

string formatDate (string &oldFormat)
{
string newFormat;

newFormat.push_back(oldFormat[6]);
newFormat.push_back(oldFormat[7]);
newFormat.push_back('/');
newFormat.push_back(oldFormat[4]);
newFormat.push_back(oldFormat[5]);
newFormat.push_back('/');
newFormat.push_back(oldFormat[0]);
newFormat.push_back(oldFormat[1]);
newFormat.push_back(oldFormat[2]);
newFormat.push_back(oldFormat[3]);
return newFormat;
}

The function for formatTime is very similar. Can anyone give me any
help on how to use better programming to change the format, using
something from the standard template library maybe?

Cheers
Dave

 

[Mike Wahler]

Hi,
this should be a pretty easy question for the advanced people on
here. Basically , I have two strings:

string transDate = "20030901";
string transTime = "1200";

I want to know the best way to reformat them into a more recognisable
format so that:

transDate = "01/09/2003";
transTime = "12:00";

At the moment I just have a function like this:

string formatDate (string &oldFormat)
{
string newFormat;

newFormat.push_back(oldFormat[6]);
newFormat.push_back(oldFormat[7]);
newFormat.push_back('/');
newFormat.push_back(oldFormat[4]);
newFormat.push_back(oldFormat[5]);
newFormat.push_back('/');
newFormat.push_back(oldFormat[0]);
newFormat.push_back(oldFormat[1]);
newFormat.push_back(oldFormat[2]);
newFormat.push_back(oldFormat[3]);
return newFormat;
}

The function for formatTime is very similar. Can anyone give me any
help on how to use better programming to change the format, using
something from the standard template library maybe?

std::string has what you need. Consider:

#include <iostream>
#include <string>

std::string fmt_date(const std::string& date,
char delim = '/')
{
return date.substr(6, 2) + delim +
date.substr(4, 2) + delim +
date.substr(0, 4);
}

int main()
{
std::string transDate = "20030901";
std::string transTime = "1200";

std::cout << transDate << '\n'
<< fmt_date(transDate) << '\n';

return 0;

}


There are of course many more ways to skin this
particular cat. I think you can take it from
here and do the time formatting.

HTH,
-Mike

 

[Guest]

Hi,
this should be a pretty easy question for the advanced people on
here. Basically , I have two strings:

string transDate = "20030901";
string transTime = "1200";

I want to know the best way to reformat them into a more recognisable
format so that:

transDate = "01/09/2003";
transTime = "12:00";

At the moment I just have a function like this:

string formatDate (string &oldFormat)
{
string newFormat;

newFormat.push_back(oldFormat[6]);
newFormat.push_back(oldFormat[7]);

std::string formatDate(string &oldFormat) {
std::string newFormat(oldFormat.size()+2,'/');
newFormat.replace(0,2,oldFormat,6,2);
newFormat.replace(3,2,oldFormat,4,2);
newFormat.replace(5,4,oldFormat,0,4);
return newFormat;
}

newFormat.push_back('/');
newFormat.push_back(oldFormat[4]);
newFormat.push_back(oldFormat[5]);
newFormat.push_back('/');
newFormat.push_back(oldFormat[0]);
newFormat.push_back(oldFormat[1]);
newFormat.push_back(oldFormat[2]);
newFormat.push_back(oldFormat[3]);
return newFormat;
}

The function for formatTime is very similar. Can anyone give me any
help on how to use better programming to change the format, using
something from the standard template library maybe?

Cheers
Dave

 

[Dj Frenzy]

cheers. i got it working no problem, much appreciated.

just a quick question though. in your answer you used

std::string instead of just string.

Whys this? Is it just a better way for programmers to know whats going
on in your code? Or does it make any difference to the program its
self?