strtod

This is a discussion on strtod within the C Programming forums, part of the General Programming Boards category; double strtod(char*,char**) i need a replacement, is there a free one? my program cannot use stdlib.h, and the target enviroment ...

  1. #1
    Just because ygfperson's Avatar
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    strtod

    double strtod(char*,char**)
    i need a replacement, is there a free one? my program cannot use stdlib.h, and the target enviroment is very picky about "standard" functions.
    could atof be used to replace this?

  2. #2
    Registered User Strider's Avatar
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    What program do you use? If you can't use the stdlib.h file, then you will not be able to use atof() either. Can you use the string.h file? As I remember, the strtod() function is defined in that header.

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  3. #3
    Just because ygfperson's Avatar
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    i'm writing a graphing calculator for a pda(vtech helio) which uses weird libs. i have the parser for the equation from snippets.org, but it needs strtod. my compiler is gcc, although i don't know what version. the compiler, linker, etc.. are all dos programs. I know i definitely cannot use stdlib.h, but i'm not sure about string.h. i doubt it, though.

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    Registered User alex's Avatar
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    Can't you use "sscanf" from stdio.h?

    alex

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    Just because ygfperson's Avatar
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    can't use stdio.h either.

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    Hamster without a wheel iain's Avatar
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    why cant you use stdio.h ?
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    and the hat of int overfl Salem's Avatar
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    Well a really simple - no error checking - atoi would look like this

    Code:
    char buff[] = "1234";  // for example
    int result = 0;
    int i;
    for ( i = 0 ; buff[i] != '\0' ; i++ ) {
        result = result * 10 + buff[i] - '0';
    }

  8. #8
    Just because ygfperson's Avatar
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    the sdk for this pda doesn't include most normal functions. check out the message board at pdabuzz.com -> other platforms -> vtech -> vtech software development for more info. it also sucks at float calculations, although double works.

    would i be correct if i said that:
    1)strtod(char* sz1,char** psz2) takes the beginning characters of the string sz1 and stopped when it wasn't a number anymore, where that pointer would be passed back through psz2?
    2) would i be correct in assuming that the psz2 is not needed most of the time? from eval.c:
    Code:
    if (0.0 == (arg = strtod(str, &endptr)) && .....
    endptr appears only twice in eval.c: when it's defined and here. i'm thinking if it's not needed, something like atof could be used instead.

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