Expert: Zlatko - 5/4/2010

Question
Hi Zelatko,
I've a program that it doesn't work.Could you help me.
It's a part of a program.I want to check two dates with this program that if are the correct date or not!

Regards,
Tina

#include <iostream>
#include <iomanip>
#include <sstream>
using namespace std;

string correctdate(string date);
int main()
{
string d1,date1;//,d2,date1,date2;
/*date1 = correctdate(d1);
date2 = correctdate(d2);*/
 d1 = correctdate(date1);
//correctdate(d2);
//cout<<"date1"<<date1<<endl;
//cout<<"date2"<<date2<<endl;
return 0;
}
//------------------------------------------
//namn:correctdate
//------------------------------------------
string correctdate()
{
int year, month,day;
string date;
bool dateok ;
do
{
  dateok = true;
cout<<"\t**********DATE**********\n";
cout<<"\t write a date (like 1111 11 11): ";
getline(cin,date);


date[4] =' ';
date[7] =' ';
istringstream iss(date);
iss>>year>>month>>day;


if (year<1900 || year>3000)
{dateok = false;}

if (month<1 || month>12)
{dateok = false;}

if(day <1 || day >31)
{dateok = false;}

cout<<endl;
cout<<"\tYear = "<<year<<endl;
cout<<"\tMonth = "<<month<<endl;
cout<<"\tDay = "<<day<< " is a ";

if (dateok)
{cout<<"date is okey ."<<endl;}
else
{cout<<" date is not okey.try again !!!"<<endl<<endl;}

}while(!dateok);
return date;
}

Answer
Hello Tina.

Your program almost works. There are just a couple of problems with it. One problem is that you declared the function
string correctdate(string date);

but defined the function
string correctdate()
{
}

The function you defined took no parameters, so the program would not link. The linker was expecting a function that took a string.

The other problem is explained in my comments in the code. My comments start with ZM, so you can search for that.


Best regards
Zlatko

#include <iostream>
#include <iomanip>
#include <sstream>
using namespace std;

string correctdate(void);

int main()
{
   string d1;
   d1 = correctdate();
   return 0;
}

//------------------------------------------
//namn:correctdate
//------------------------------------------
string correctdate(void)
{
   // ZM initialize your local variables
   int year = 0, month = 0, day = 0;

   string date;
   bool dateok ;
   do
   {
       dateok = true;
       cout<<"\t**********DATE**********\n";
       cout<<"\t write a date (like 1111 11 11): ";
       getline(cin,date);


       /*ZM This will overwrite data, if the user inputs something like 2000 1 1
       If the spaces are not there already, you cannot just put them in because doing
       so will overwrite the user input.
       date[4] =' '; // Remove this line
       date[7] =' '; // Remove this line
       If the spaces are missing, the iss>> will fail, and the variables
       month or day will stay 0, because they are initialized to 0 above.
       Then your program will report the error at the end.
       */
       istringstream iss(date);
       iss>>year>>month>>day;

       if (year<1900 || year>3000)
       {dateok = false;}

       if (month<1 || month>12)
       {dateok = false;}

       if(day <1 || day >31)
       {dateok = false;}

       cout<<endl;
       cout<<"\tYear = "<<year<<endl;
       cout<<"\tMonth = "<<month<<endl;
       cout<<"\tDay = "<<day<< " is a ";

       if (dateok)
       {cout<<"date is okey ."<<endl;}
       else
       {cout<<" date is not okey.try again !!!"<<endl<<endl;}

   }while(!dateok);
   return date;
}