C++ newbie needs help with simple conversion programming

This is a discussion on C++ newbie needs help with simple conversion programming within the C++ Programming forums, part of the General Programming Boards category; Hi, I'm trying to make a program that converts Fahrenheit into Celsius and Kelvin. #include <iostream> #include <cmath> #include <cstdlib> ...

  1. #1
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    C++ newbie needs help with simple conversion programming

    Hi, I'm trying to make a program that converts Fahrenheit into Celsius and Kelvin.

    #include <iostream>
    #include <cmath>
    #include <cstdlib>

    int main(int argc, char *argv[])
    {
    double fah, cel, kel;
    char ans;
    do
    {
    cout<<"Enter the temperature in Fahrenheit: "; // I get error here..."cout" undeclared
    cin>>fah;

    cel = (5.0 / 9.0) * (fah - 32.0);
    kel = (cel + 273.0);

    cout<<"The temperature is "<<cel<<" degree Celsius and "<<kel<<" Kelvin."<<endl;
    cout<<endl<<endl
    <<"Do you want to do this again? ";
    cin>>ans;
    fflush(stdin);
    }while(ans=='Y' || ans == 'y');
    system("PAUSE");
    return EXIT_SUCCESS;
    }
    Last edited by djayyyyy; 10-16-2010 at 10:43 PM.

  2. #2
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    You either need to add
    Code:
    using namespace std;
    before main() or use
    Code:
    std::cout<<"Enter the temperature in Fahrenheit: ";
    std::cin>>fah;
    and all other things in the std namespace.

    Jim

  3. #3
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    Also do not
    Code:
    fflush(stdin);
    Jim

  4. #4
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    And to quibble, zero degrees celcius is 273.15 kelvin
    Right 98% of the time, and don't care about the other 3%.

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    Thanks for the replies!

    But I get another error in next line

    #include <iostream>
    #include <cmath>
    #include <cstdlib>

    int main(int argc, char *argv[])
    {
    double fah, cel, kel;
    char ans;
    do
    {
    cout<<"Enter the temperature in Fahrenheit: ";
    cin>>fah; // I get error here now... it says expected 'while' '(' before 'cin' and ')' before ';'

    cel = (5.0 / 9.0) * (fah - 32.0);
    kel = (cel + 273.0);

    cout<<"The temperature is "<<cel<<" degree Celsius and "<<kel<<" Kelvin."<<endl;
    cout<<endl<<endl
    <<"Do you want to do this again? ";
    cin>>ans;
    }while(ans=='Y' || ans == 'y');
    system("PAUSE");
    return EXIT_SUCCESS;
    }

  6. #6
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    You code ran just fine for me. I have no idea what you're talking about. you might add using namespace std somewhere. Also, I have no such program as "PAUSE", so there was a runtime error on that. If you just want it to wait a second before exiting, you can sleep(1000);

  7. #7
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    Quote Originally Posted by QuadraticFighte View Post
    You code ran just fine for me. I have no idea what you're talking about. you might add using namespace std somewhere. Also, I have no such program as "PAUSE", so there was a runtime error on that. If you just want it to wait a second before exiting, you can sleep(1000);
    What I wanted to do is ask the person if he/she wants to try another conversion.
    And maybe I might have messed up something while I was copying and pasting and fixing stuff at the same time...

    I'll try to program this from scratch.

    ----------------------------------------------------------EDIT---------------------------------------------------------------------

    Okay I started the program from scratch again and I get no errors and its perfectly fine until
    I get to the last part where it asks me if I want to do it again. This is what happens http://img202.imageshack.us/img202/1919/11111lj.png

    #include <cstdlib>
    #include <iostream>
    #include <cmath>

    using namespace std;

    int main(int argc, char *argv[])
    {
    char ans;
    double f,c,k;
    {
    cout<<"Enter the temperature in Fahrenheit: ";
    cin>>f;

    c = (5.0 / 9.0) * (f - 32.0);
    k = (c + 273.15);

    cout<<"The temperature is "<<c<<" degree Celsius and "<<k<<" Kelvin."<<endl;

    cout<<"Do you want to do this again? ";
    cin>>ans;
    }while(ans=='Y' || ans == 'y');
    system("PAUSE");
    return EXIT_SUCCESS;
    }
    Last edited by djayyyyy; 10-17-2010 at 02:12 PM.

  8. #8
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    That's because you left out the do in the do while loop. Right before your bracket after the line double f,c,k; On my text editor, it's line 12. What was happening was without the do, you just had a block of code and then

    Code:
    while(ans=='Y' || ans == 'y');
    This is a valid C statement which means "while ans is either y or Y do nothing" So you were stuck in an infinite loop.

  9. #9
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    Quote Originally Posted by QuadraticFighte View Post
    That's because you left out the do in the do while loop. Right before your bracket after the line double f,c,k; On my text editor, it's line 12. What was happening was without the do, you just had a block of code and then

    Code:
    while(ans=='Y' || ans == 'y');
    This is a valid C statement which means "while ans is either y or Y do nothing" So you were stuck in an infinite loop.
    SWEEEET. THANK YOU SOO MUCH for helping this newbie out

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