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Thread: char to const char* with atof

  1. #1
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    Default char to const char* with atof

    Hello, I have this problem; it gets a runtime error. Why?
    Qt Code:
    1. vector<double> vec;
    2. string s =" 123213131313131331";
    3. string::iterator it_s = s.begin();
    4. for ( ; it_s != s.end(); ++it_s) {
    5. vec.push_back( (double) atof( (const char *) (*it_s) ) ); //runtime error
    6. }
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    Last edited by mickey; 29th February 2008 at 00:49.
    Regards

  2. #2
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    Default Re: char to const char* with atof

    You can't cast a char to const char * like that... atof() expects adress of a C string and outputs a float. What are you trying to achieve?

  3. #3
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    Default Re: char to const char* with atof

    I edited it. maybe more clear now (convert each digit to double and psuh into vector)
    Regards

  4. #4
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    Default Re: char to const char* with atof

    Khem.... Lot to learn you still have, young one

    Qt Code:
    1. QVector<double> vec;
    2. std::string str;
    3. for(int i=0;i<str.length();i++){
    4. int val = str[i] - '0';
    5. if(val<0 || val>9) continue;
    6. vec.push_back((double)val);
    7. }
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  5. #5
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    Default Re: char to const char* with atof

    thanks but isn't there a way to use that iterator on the string, please?
    EDIT: and why a cast at C style ( "(double)" I mean )
    Last edited by mickey; 29th February 2008 at 01:11.
    Regards

  6. #6
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    Default Re: char to const char* with atof

    Use an iterator if you want - I don't mind. The heart of the solution is the conversion of a character to digit, not the way you traverse the string. The cast is "just in case" so that I'm more confident it compiles.

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