Chemistry Problem In C++ Script Not WORKING

This is a discussion on Chemistry Problem In C++ Script Not WORKING within the C++ Programming forums, part of the General Programming Boards category; O.K. I'm very very new to C++ but I am trying to make a programm that can do PV=nRT and ...

  1. #1
    Registered User
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    Mar 2008
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    Chemistry Problem In C++ Script Not WORKING

    O.K. I'm very very new to C++ but I am trying to make a programm that can do PV=nRT and for whatever you put 0 in for it solves the equation out. But when I was trying to test if I could get even one of the variables solved I came into a problem, it's not giving me the right answer XD.
    Here is my script
    Code:
    #include <iostream>
    
    using namespace std;
    
    
    int main()
    {
        int P;
        float V;
        float r;
        float n;
        float temp;
        float answer;
        
        cout<<"Please enter value for Pressure in kPa \n";
        cin>> P;
        cin.ignore ();
        cout<<"Please enter value for Volume in L \n";
        cin>> V;
        cin.ignore ();
        cout<<"Please enter value for n in moles \n";
        cin>> n;
        cin.ignore ();
        cout<<"Please enter value for Temperature in Celsius \n";
        cin>> temp;
        cin.ignore ();
        r = 8.31; 
    
    if ( P = 0 ) { answer = n * r * temp / V; }
    cout<<answer; 
    cin.ignore();
    cin.get ();
    }

  2. #2
    Kernel hacker
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    You don't think that could be caused by the temperature beign in Celsius rather than Kelvin?

    --
    Mats
    Compilers can produce warnings - make the compiler programmers happy: Use them!
    Please don't PM me for help - and no, I don't do help over instant messengers.

  3. #3
    Registered User
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    Mar 2008
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    well actually no i havent made it to add the 273 to the temp yet because i was trying just to get this small part of it to work

  4. #4
    Chinese pt foxman's Avatar
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    Code:
    if ( P = 0 ) { answer = n * r * temp / V; }
    Use the "==" operator instead of the "=" operator. That way, the calculation will perform (since "P = 0" evaluates to 0, you never actually do the calculation).

  5. #5
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    Thank you so much foxman. That worked WOOT. You rock man.

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