Math Problems?

This is a discussion on Math Problems? within the C++ Programming forums, part of the General Programming Boards category; I have this code: Code: #include <iostream> using namespace std; int bday; int bmonth; int byear; int cday; int cmonth; ...

  1. #1
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    Sep 2007
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    Math Problems?

    I have this code:
    Code:
    #include <iostream>
    
    using namespace std;
    
    int bday;
    int bmonth;
    int byear;
    int cday;
    int cmonth;
    int cyear;
    char cont;
    int spd;
    
    
    
    int main()
    {
        
    do{
     bday=0;
     cday=0;
     byear=0;
     cyear=0;
     cmonth=0;
     bmonth=0;
     spd=0;   
        
        
     system("cls");
     cout<< "SLEEPY TIME!" << endl;
     cout<< "This is a program that calculates how much you have time you have slept in your entire life. Hit ENTER to continue." << endl; 
     cin.get();
    system("cls");
     cout<<"How many hours on average do you sleep in a night?" << endl;
     cin>> spd;   
     system("cls");
     cout<<"What year were you born in? (example: 1994)" << endl;
     cin>> byear;
     cin.ignore();
     system("cls");
     cout<<"What month of the year were you born in? Please represent numerically (january: 1 , february: 2 , etc.)" << endl;
     cin>> bmonth;
     cin.ignore();
     system("cls");
     cout<<"What day of the month were you born? (example: 10)" << endl;
     cin>> bday;
     cin.ignore();
     system("cls");
     cout<<"What year is it currently? (example: 1994)" << endl;
     cin>> cyear;
     cin.ignore();
     system("cls");
     cout<<"What month is it currently? Please represent numerically (january: 1 , february: 2 , etc.)" << endl;
     cin>> cmonth;
     cin.ignore();
     system("cls");
     cout<<"What day of the month is it currently? (example: 10) \n";
     cin>> cday;
     cin.ignore();
     system("cls");
     
     cout<<"You have been sleeping for: "<< (cyear - byear)*(spd/24) <<" years, " << (cmonth - bmonth)*(spd/24) <<" months, and "<< (cday - bday)*(spd/24) <<" days.\n(Based on 8 hours of sleep a day, days rounded)" << endl;
    
     cout<< "0. Quit" <<endl;
     cout<< "1. Restart" <<endl;
     cin>> cont;
     cin.ignore();
     
    } while (cont);
    }
    ----------------------------------------

    The problem is that for some reason, when I put in say, 10 for cyear, cday, cmonth, byear, and bmonth, but put in 15 bday, and 1 spd, it comes out with 0 days, 0 years, and 0 months. do you know why?

    thanks.
    Last edited by Salem; 12-31-2007 at 01:35 AM. Reason: Added code tags, for all the good it'll do.

  2. #2
    Registered User ssharish2005's Avatar
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    Location
    Cambridge, UK
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    What happened to the code Tags and the code indentation, please use code tags

    Code:
    #include <iostream>
    
    using namespace std;
    
    int bday;
    int bmonth;
    int byear;
    int cday;
    int cmonth;
    int cyear;
    char cont;
    int spd;
    
    int main()
    {
        do
        {
            bday=0;
            cday=0;
            byear=0;
            cyear=0;
            cmonth=0;
            bmonth=0;
            spd=0; 
            
            system("cls");
            cout<< "SLEEPY TIME!" << endl;
            cout<< "This is a program that calculates how much you have time you have slept in your entire life. Hit ENTER to continue." << endl; 
            cin.get();
            system("cls");
            cout<<"How many hours on average do you sleep in a night?" << endl;
            cin>> spd; 
            system("cls");
            cout<<"What year were you born in? (example: 1994)" << endl;
            cin>> byear;
            cin.ignore();
            system("cls");
            cout<<"What month of the year were you born in? Please represent numerically (january: 1 , february: 2 , etc.)" << endl;
            cin>> bmonth;
            cin.ignore();
            system("cls");
            cout<<"What day of the month were you born? (example: 10)" << endl;
            cin>> bday;
            cin.ignore();
            system("cls");
            cout<<"What year is it currently? (example: 1994)" << endl;
            cin>> cyear;
            cin.ignore();
            system("cls");
            cout<<"What month is it currently? Please represent numerically (january: 1 , february: 2 , etc.)" << endl;
            cin>> cmonth;
            cin.ignore();
            system("cls");
            cout<<"What day of the month is it currently? (example: 10) \n";
            cin>> cday;
            cin.ignore();
            system("cls");
            
            cout<<"You have been sleeping for: "<< (cyear - byear)*(spd/24) <<" years, " << (cmonth - bmonth)*(spd/24) <<" months, and "<< (cday - bday)*(spd/24) <<" days.\n(Based on 8 hours of sleep a day, days rounded)" << endl;
            
            cout<< "0. Quit" <<endl;
            cout<< "1. Restart" <<endl;
            cin>> cont;
            cin.ignore();
        
        } while (cont);
    }
    ssharish

  3. #3
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    all your variables are ints and when division is performed on ints, they're rounded down

    use doubles or floats instead

    OS: Windows 7, XUbuntu 11.10, Arch Linux
    IDE: CodeBlocks
    Compiler: GCC

  4. #4
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    spd is an int, and will (presumably) have a value < 24. spd/24 will be computed using integer arithmetic, which (for positive values of spd) rounds down towards zero. This means that, if spd is between 0 and 23, then spd/24 will always have a value of zero.

  5. #5
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    Hey, I think it will not terminate even if I enter 0? Hmmm ...

  6. #6
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    @manav
    look at the last 5 lines of code
    it prompts the user for input and stores it in cont
    If cont is false (false = 0, true = 1), then it goes out of the loop

    OS: Windows 7, XUbuntu 11.10, Arch Linux
    IDE: CodeBlocks
    Compiler: GCC

  7. #7
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    Join Date
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    Yeah! And cont is declared as char!
    So it will either be '0' or '1' (if right values are entered) and none of them is false!

    Or ... am I wrong?

  8. #8
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    right, didn't see it's type. The condition will always be true.

    OS: Windows 7, XUbuntu 11.10, Arch Linux
    IDE: CodeBlocks
    Compiler: GCC

  9. #9
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    ...

    Why did I make cont a char? Duh.. Better fix that. So what should I do with spd?

    EDIT: Oh, nvm i know what to do. Thanks for all the help guys.
    Last edited by Suudsu2200; 12-31-2007 at 09:39 AM.

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