Cast double to const char*

[prushik]

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.

[amt_muk]

U can try sprintf().

Amit

[Ancient Dragon]

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.

[Ptolemy]

>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.

[vmanes]

Here's an interesting discussion on the topic:
http://www.codeproject.com/string/string_conversions.asp

[Seta00]

http://www.cplusplus.com/reference/clibrary/cstdio/sprintf.html
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