trying to display two digits

This is a discussion on trying to display two digits within the C++ Programming forums, part of the General Programming Boards category; How do i display cout << 1; in two digits '01'...

  1. #1
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    trying to display two digits

    How do i display cout << 1; in two digits '01'

  2. #2
    C++ Witch laserlight's Avatar
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    One option is to use std::setw and std::setfill from <iomanip>, e.g.,
    Code:
    cout << setw(2) << setfill('0') << 1;
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  3. #3
    Technical Lead QuantumPete's Avatar
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    Code:
     #include <iomanip>
    std::cout << std::setw(2) << std::setfill('0') << 1;
    QuantumPete
    "No-one else has reported this problem, you're either crazy or a liar" - Dogbert Technical Support
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  4. #4
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    Quote Originally Posted by QuantumPete View Post
    Code:
     #include <iomanip>
    std::cout << std::setw(2) << std::setfill('0') << 1;
    QuantumPete
    for some reason it puts the zero after the digit 1 becomes 10 ..

    Code:
    		cout  << left << setw(2) << setfill('0') << iter->getIssueDate().getDay()  << " / " << left << setw(2) 
    			 << iter->getIssueDate().getMonth()  << " / " << left << setw(6) << iter->getIssueDate().getYear();
    		cout  << iter->getIssueDate().getHour() << ":" << iter->getIssueDate().getMinute();

  5. #5
    C++ Witch laserlight's Avatar
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    for some reason it puts the zero after the digit 1 becomes 10 ..
    Perhaps you set the justification to left in some earlier portion of the code, so just set it to right, e.g.,
    Code:
    cout << setw(2) << setfill('0') << right << 1;
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  6. #6
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    Quote Originally Posted by laserlight View Post
    Perhaps you set the justification to left in some earlier portion of the code, so just set it to right, e.g.,
    Code:
    cout << setw(2) << setfill('0') << right << 1;
    I thought as so, but i need it left..

    Code:
    	// Date [01/01/2008]
    	cout << left << setw(2) << setfill('0') << iter->getIssueDate().getDay();
    	cout << " / " << left << setw(2) << iter->getIssueDate().getMonth();
    	cout << " / " << left << setw(6) << iter->getIssueDate().getYear();
    
    	// Clock [12:45]
    	cout << iter->getIssueDate().getHour() << ":" << iter->getIssueDate().getMinute();
    Also, why is this 0 inserted to all the following couts following it, how do i enforce it to only one variable/value ?

  7. #7
    C++ Witch laserlight's Avatar
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    I thought as so, but i need it left..
    For the printing of this date, set the justification to right, then change it back to left afterwards.

    Also, why is this 0 inserted to all the following couts following it, how do i enforce it to only one variable/value ?
    You can setfill(' ') after you are done. More generally when you are overloading operator<<, save the format flags before you begin changing them, then restore them after you are done.
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  8. #8
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    Quote Originally Posted by laserlight View Post
    For the printing of this date, set the justification to right, then change it back to left afterwards.


    You can setfill(' ') after you are done. More generally when you are overloading operator<<, save the format flags before you begin changing them, then restore them after you are done.
    Just checking
    Code:
    cout << "[" << right << setw(2) << setfill('0') <<  left <<  iter->getIssueDate().getDay() ;
    cout << setfill(' ');
    No! this doesn't work .. Still puts zero's after
    Last edited by csonx_p; 09-01-2008 at 12:05 PM.

  9. #9
    The larch
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    You could also just print the year followed by two spaces (instead of the year with width 6), then the time and finally set the alignment and fill character back just once.

    But in any case, formatted output is usually simpler with format strings, e.g with boost::format

    Code:
    std::cout << boost::format("&#37;02d/%02d/%d  %02d:%02d") % 1 % 8 % 1946 % 14 % 8 << '\n';
    I might be wrong.

    Thank you, anon. You sure know how to recognize different types of trees from quite a long way away.
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  10. #10
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    Quote Originally Posted by anon View Post
    You could also just print the year followed by two spaces (instead of the year with width 6), then the time and finally set the alignment and fill character back just once.

    But in any case, formatted output is usually simpler with format strings, e.g with boost::format

    Code:
    std::cout << boost::format("%02d/%02d/%d  %02d:%02d") % 1 % 8 % 1946 % 14 % 8 << '\n';
    Cool, looks more a c style , printf() .. thanx

  11. #11
    C++ Witch laserlight's Avatar
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    No! this doesn't work .. Still puts zero's after
    That's because you set the justification back to left before you actually print the number.
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  12. #12
    Kernel hacker
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    Another option, which may make your entire date-printing easier to handle, would be to have a "tostring" function (and a "fromstring"?) in your Date class, that produces a std::string.

    --
    Mats
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