addition, multiplication errors??

This is a discussion on addition, multiplication errors?? within the C Programming forums, part of the General Programming Boards category; I am currently experiencing some difficulty when it comes to simple athrimitics in C. I am using variables that are ...

  1. #1
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    Exclamation addition, multiplication errors??

    I am currently experiencing some difficulty when it comes to simple athrimitics in C. I am using variables that are double, so should be able to handle decimal, multiplying them and/or dividing them by another variable, also a double, and when I go to display the result using for example
    Code:
    printf("%d", bla)
    I get a return of 0 instead of the number I am suppose to get. This happens is several places in my program and I can't figure out why, in some of the arithmitics I am using hex. values (ex. 0xA) but I don't see why that should make a difference.

    If you can offer me any advice it would be greatly appreciated

    Thanks

  2. #2
    ATH0 quzah's Avatar
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    Use %f for floating point numbers. %d is for integers.

    Quzah.
    Hope is the first step on the road to disappointment.

  3. #3
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    Ok that is well and good, and I can't believe I didn't think of that, but I'm still stuck with one problem. I am receiving data from an data acquisition board, which returns the data to me in hex. I then need to do some calculation to that value, which I am doing in hex. then show it in decimal. So far when I do my calculations all I do get is 0 as an answer. Below is a segment of the code being used
    Code:
    finalResult = (datavalue/calcValue)*calcValue1;
    fprintf(outOpen,"    %f",finalResult);
    where datavalue is the value recieved from the board in hex. calcValue is 0x1000 and calcValue1 is 0x14.

    When I get a value like 2 from the board I should still be recieving a final value print out of something like 0.002 but I am getting 0. Same with bigger numbers like 153 as a returned value from the board.

    If you can give me any advice, once again it would be greatly apprieciated

    Thanks

  4. #4
    Been here, done that.
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    You're doing all integer math, which will truncate your division to 0. Cast the values to float on the right side of your equal
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