Hello Programmers! How can I convert a double to a string without losing its precision (i.e. values after the decimal point)?

Thanks!

how many digits after the decimal point do you want? You can use sprintf() to do it. See this article

``````double n = 1.234678901234567890;
char str[10];
sprintf(str,"%.5f", n);
``````

How can I do it with sprintf()? Before I posted here, I scoured the internet all over, and all the explanations for sprintf were to complicated. I couldn't understand.

If AD's example above was too complicated, I'm not sure what to tell you, because that's as simple as …

## All 7 Replies

how many digits after the decimal point do you want? You can use sprintf() to do it. See this article

``````double n = 1.234678901234567890;
char str[10];
sprintf(str,"%.5f", n);
``````

I want two digits after the decimal point when the double is converted to a string. How can I do it with sprintf()? Before I posted here, I scoured the internet all over, and all the explanations for sprintf were to complicated. I couldn't understand.

How can I do it with sprintf()? Before I posted here, I scoured the internet all over, and all the explanations for sprintf were to complicated. I couldn't understand.

If AD's example above was too complicated, I'm not sure what to tell you, because that's as simple as it gets. For your specific needs:

``````double n = 1.23456;
char s[10];

sprintf(s, "%.2f", n);
``````

In C++ there are many more options, but I suspect those will confuse you as well. The usual solution involves `stringstream`s:

``````double n = 1.23456;
ostringstream oss;

oss.precision(2);
oss << fixed << n;

string s = oss.str();
``````

In sprintf(), the "%.5f" says to print a double (that's what the 'f' means) with 5 digits following the decimal point. So if you only want 2 digits then just change the 5 to a 2.

I don't want a c-style string. I want a regular class <string> string that is stored in a var., not printed. How can I do that?

How can I do that?

You could actually read this thread instead of guessing at what people are saying. I posted how to do it with std::string.

Thank you! I was careless. Problem solved.

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