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Cast double to const char*
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Join Date: Oct 2007
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Junior Poster in Training
I would like to know once and for all how to convert a double to a const char*
I've tried it a few times, but have never succeeded, I know it can be done, but I haven't figured out how to yet. I've tried some different things. Sometimes it won't compile, and sometimes the program crashes, and other times it ends up as an empty string.
I've tried it a few times, but have never succeeded, I know it can be done, but I haven't figured out how to yet. I've tried some different things. Sometimes it won't compile, and sometimes the program crashes, and other times it ends up as an empty string.
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Join Date: Aug 2005
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depends on how you want to use it. If you want to pass a pointer to a double as a parameter to some function that takes char* then typecasting might work, depending on what that function is going to do with it. Normally, however, you will have to convert it storing the results in either a character array or a std::string object.
Two ways come to mind: sprintf() will convert and store in a character array, while std::stringstream will convert and store in std::string object.
Two ways come to mind: sprintf() will convert and store in a character array, while std::stringstream will convert and store in std::string object.
Don't PM me with questions -- you might get a nasty PM in response. If you have a question then post it in one of the forums.
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Join Date: Oct 2007
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Junior Poster in Training
>I would like to know once and for all how to convert a double to a const char*
Casting doesn't work. You're not converting the double to a string with a cast, you're telling the compiler to use the binary representation of the double as characters in a string. For a value like 12.35, that's not going to give you a string like "12.35". You need to take the printed value (like if you write the double using cout) and store it in a string. That's really really painful to do manually with floating-point, so you should use sprintf or stringstream like Ancient Dragon said.
Casting doesn't work. You're not converting the double to a string with a cast, you're telling the compiler to use the binary representation of the double as characters in a string. For a value like 12.35, that's not going to give you a string like "12.35". You need to take the printed value (like if you write the double using cout) and store it in a string. That's really really painful to do manually with floating-point, so you should use sprintf or stringstream like Ancient Dragon said.
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Join Date: Aug 2007
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Here's an interesting discussion on the topic:
http://www.codeproject.com/string/st...onversions.asp
http://www.codeproject.com/string/st...onversions.asp
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