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Help with solving Order of Ops Question

This is a discussion on Help with solving Order of Ops Question within the C Programming forums, part of the General Programming Boards category; I'm stuck on a question in my assignment that's asking me to create a program to calculate the Area-cubed of ...

  1. #1
    Registered User Psyzen's Avatar
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    Question Help with solving Order of Ops Question

    I'm stuck on a question in my assignment that's asking me to create a program to calculate the Area-cubed of a cylinder knowing that
    Pi = 3.14159 and Radius = 2.2
    the formula is 4/3 Pi R^3
    and this is the code I have written down:

    Code:
    #include<stdio.h.>
    #include<math.h>
    main()
    {
    float Pi = 3.14159, num1 = pow(2.2,3), area;
    area = 4 / 3 * num1;
    printf("%f", area);
    getch();
    }
    I'm getting different answers if I instead make the 4 / 3 into 1.25, so I was wondering how do I signify the operations in the order it should be in, if it should be according to PEMDAS(which i believe it should be)?

    Thanks in Advance!

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    C++ Witch laserlight's Avatar
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    Be wary of integer division here, e.g., change 4 / 3 to 4.0 / 3.0
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    Registered User Psyzen's Avatar
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    Quote Originally Posted by laserlight View Post
    Be wary of integer division here, e.g., change 4 / 3 to 4.0 / 3.0
    I changed the ints to floating point values and I'm getting a number like 14.121337 where it should be somewhere closer to 33-34

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    C++ Witch laserlight's Avatar
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    Oh, but of course, mathematically, 4/3 is not equal to 1.25.

    Plus, I note that you computed 2.2 to the power of 3, but did not multiply by pi.
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    Registered User Psyzen's Avatar
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    Quote Originally Posted by laserlight View Post
    Oh, but of course, mathematically, 4/3 is not equal to 1.25.

    Plus, I note that you computed 2.2 to the power of 3, but did not multiply by pi.
    Of course it doesn't! haha thanks for the help.

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    Looks more like the formula of volume of sphere. If you are working with a cylinder where's the height parameter?

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