Newbie's If Statement

This is a discussion on Newbie's If Statement within the C++ Programming forums, part of the General Programming Boards category; Here is my code: Code: #include <iostream> using namespace std; // Hello World! int main() { //Variables For Hello World! ...

  1. #1
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    Newbie's If Statement

    Here is my code:

    Code:
    #include <iostream>
    
    using namespace std;
    
    // Hello World!
    
    int main()
    {
        //Variables For Hello World!
        int month, year, specialnumber;
    
      cout<<"Please enter your birth month:";
      cin>> month;
      cin.ignore();
      cout<<"Please enter your birth year:";
      cin>> year;
      cin.ignore();
      cout<<"Your special number is "<< month * year + year - month<<"\n";
      cin>> specialnumber;
      cin.ignore();
      if ( specialnumber < 150 ) {                 
         cout<<"Your number is unlucky!\n"; 
      }
      else if ( specialnumber == 151 ) {            
         cout<<"Go buy a lottery ticket!\n";          
      }
      else {
        cout<<"Your special number is lucky.  Pet a wet dog!\n";     
      }
      cin.get();
      
    }
    It is supposed to change the inputted numbers and then check to see if the number is higher, lower, or equal to a certain number. Then it reads back whether or not your "lucky". It compiles fine, but it will not show the text after the number is calculated.

  2. #2
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    Code:
    #include <iostream>
    
    using namespace std;
    
    // Hello World!
    
    int main()
    {
        //Variables For Hello World!
        int month, year, specialnumber;
    
      cout<<"Please enter your birth month:";
      cin>> month;
      cout<<"Please enter your birth year:";
      cin>> year;
      specialnumber = (month * year + year - month);
      cout<<"Your special number is "<< specialnumber <<"\n";
      if ( specialnumber < 150 ) 
    {                 
         cout<<"Your number is unlucky!\n"; 
      }
      else if ( specialnumber == 151 ) 
    {            
         cout<<"Go buy a lottery ticket!\n";          
      }
      else 
    {
        cout<<"Your special number is lucky.  Pet a wet dog!\n";     
      }
      cin.get();
      return 0;
    }
    you had cin >> specialnumber which was calling for a number to be inputted. Then that number would have been specialnumber.

  3. #3
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    Oh I see, thanks!

    Also, while I am on this tutorial, what does ignore do? And what does return=0 do? I read the tutorial but it is a bit confusing in those areas.

  4. #4
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    "return 0;" tells the computer that your function executed with no errors.
    "cin.ignore();" is used to skip remaining characters, how many times and what character, (I'm not 100% sure so don't quote me on that).

  5. #5
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    Quote Originally Posted by rabbit
    "return 0;" tells the computer that your function executed with no errors.
    "cin.ignore();" is used to skip remaining characters, how many times and what character, (I'm not 100% sure so don't quote me on that).
    without any arguments, ignore() means "throw away the next character" (quite often used to get rid of a newline, delimiter or whitespace).

    With 2 arguments, it may throw away up-to a number of characters, or up-to a delimiter character of your choosing (whichever comes first)

    the maximum size of the stream is found in the standard library -
    std::numeric_limits<std::streamsize>::max()

    (you can pass that as the first argument to ignore() if you wish to empty the stream - the 2nd argument will be the delimiter character)

  6. #6
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    That code automatically closes the window, within a second of entering the second amount, the birth year. Is there anyway to combat that?
    Last edited by Gallivan; 03-01-2006 at 07:32 PM.

  7. #7
    The Richness... Richie T's Avatar
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    three little letters: FAQ
    No No's:
    fflush (stdin); gets (); void main ();


    Goodies:
    Example of fgets (); The FAQ, C/C++ Reference


    My Gear:
    OS - Windows XP
    IDE - MS Visual C++ 2008 Express Edition


    ASCII stupid question, get a stupid ANSI

  8. #8
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    Alright, alright, don't eat me.

    But the thing is, it doesn't just pop-up at the start, it closes halfway through.

  9. #9
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    Try running it from a console. IE, cd dir-name; ./prog-name

    This is all in the FAQ that Richie T posted.

  10. #10
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    The cin.ignore()'s were removed in the second bit of code, so the trailing newline after the user input was not ignored. Later, the cin.get() call (which usually would pause the program) immediately reads in the newline left from the user input and does not leave the window open until you hit enter again.

    To fix it, put the ignore()'s back in, or at the very least, add one before the cin.get() at the end.

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