Began learning strings: Need to split one string into multiple

[TL29]

I am writing my first program using strings. In the program, I need to read in the date in a specific format and then do a whole bunch of stuff with that information.

However, I am stuck very early on. I need to write a function that will takes the 1 string containing the date and, split it into 3 separate strings: one for the month, one for the day, one for the year.

For example, if I was to enter 5/10/13, it would set month to 5, day to 10, and year to 13

I decided the easiest way to do this was to create 3 substrings out of it, but that wasn't yielding proper results. So, instead, I decided to try getting the first substring, then erasing that part of the string, getting another, erasing, etc.

Full program: http://pastebin.com/ezHwieuq

The function in question:

void breakoriginaldate (string origdate, string &month, string &day, string &year) 
{ 
int slash;
slash=origdate.find("/",0);
month=origdate.substr(0,slash);
cout<<month<<" is the month"<<endl;

origdate.erase(0, slash);
slash=origdate.find("/",0);
day=origdate.substr(0,slash);
cout<<day<<" is the day"<<endl;

origdate.erase(0, slash);
year=origdate;
cout<<year<<" is the year"<<endl;

return;
}

Getting the month out of it is simple, but I cannot figure out the proper way to get the day and year.

[TL29]

I changed the function to use origdate.erase(0, slash++); instead, but it is still yielding faulty results.

Here's the output:

Please enter the date in MM/DD/YY format, seperated by slashes.
For example, 6/11/08
1/23/88
1/23/88 is the original date
1 is the month
 is the day
/23/88 is the year

[TL29]

Alright, I think I solved it by changing it to slash+1 instead of slash ++

[doug4]

Try this. It is a little verbose, but is shows you how the find and substr functions can be used without erasing the original string.

#include <iostream>
using namespace std;

int main()
{
	string date = "5/1/2012";

	int monthDelim = date.find("/", 0);
	int dateStart = monthDelim + 1;
	int dateDelim = date.find("/", dateStart);
	int yearStart = dateDelim + 1;

	cout << "Date: " << date << endl; 
	cout << "MonthDelim: " << monthDelim << endl;
	cout << "DateDelim: " << dateDelim << endl;

	cout << "Month: " << date.substr(0, monthDelim) << endl;
	cout << "Date: " << date.substr(dateStart, dateDelim - dateStart)
		<< endl;
	cout << "Year: " << date.substr(yearStart) << endl;

	return 0;
}

[newbieg]

I'm kind of new to C++ as well, but I think I have an option for you. instead of passing the date into an INT, try passing it into a STRING. When a line is passed into a string it's actually being written into an array[]. then you just make a function with length() to determine where in the array to take your numbers. or run an if() test to find the slashes.

example;
string date = "05/01/12" //in the string date each number is placed in an array named date[]
string day, month, year;
int slashcount = 0
string end="no"
while(end=="no")
{
if(date[count]!="/" && slashcount==0)
{
day+=date[count]
count++
}
else if(slashcount==0)
{
slashcount++
count++
}
if(date[count]!="/" && slashcount==1)
{
month+=date[count]
count++
}
else if(slashcount==1)
{
slashcount++
count++
}
//... and do the same for year... then end the code.
//If you use length() to get the length of the date entered then you could be sure to end at the right time
}


This is not working code, just an example that I wrote here, there's probably an existing function in c++ to do what you want, but this was the idea I came up with. hope it helps. you should also look into the getline() function, I'm not entirely sure if that would do the same thing or better.

[Cubbi]

It could be easier to parse it using the I/O streams:

#include <string>
#include <sstream>
#include <iostream>
int main()
{
    std::string data = "5/1/2012";
    std::istringstream buf(data);
    int mon, day, year;
    char c1, c2;
    if( buf >> mon >> c1 >> day >> c2 >> year && c1=='/' && c2 == '/')
        std::cout << "month = " << mon << '\n'
                  << "day = " << day << '\n'
                  << "year = " << year << '\n';
    else
        std::cout << "Invalid date\n";
}

In general, there are many ways to tokenize a string in C++, especially if you can use boost, and using string::find() and string::substr() is probably the most laborous approach.