char string[20]; double d = 3.1415926; snprintf(buffer, 20, "%f", d); More on reddit.com

Please ensure that: Your code is properly formatted as code block - see the sidebar (About on mobile) for instructions You include any and all error messages in full You ask clear questions You demonstrate effort in solving your question/problem - plain posting your assignments is forbidden (and such posts will be removed) as is asking for or giving solutions. Trying to solve problems on your own is a very important skill. Also, see Learn to help yourself in the sidebar If any of the above points is not met, your post can and will be removed without further warning. Code is to be formatted as code block (old reddit: empty line before the code, each code line indented by 4 spaces, new reddit: https://i.imgur.com/EJ7tqek.png ) or linked via an external code hoster, like pastebin.com, github gist, github, bitbucket, gitlab, etc. Please, do not use triple backticks (```) as they will only render properly on new reddit, not on old reddit. Code blocks look like this: public class HelloWorld { public static void main(String[] args) { System.out.println("Hello World!"); } } You do not need to repost unless your post has been removed by a moderator. Just use the edit function of reddit to make sure your post complies with the above. If your post has remained in violation of these rules for a prolonged period of time (at least an hour), a moderator may remove it at their discretion. In this case, they will comment with an explanation on why it has been removed, and you will be required to resubmit the entire post following the proper procedures. To potential helpers Please, do not help if any of the above points are not met, rather report the post. We are trying to improve the quality of posts here. In helping people who can't be bothered to comply with the above points, you are doing the community a disservice. I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns. More on reddit.com

The short answer is that you can’t. The long answer is that 5.0 and 5.00000 are the same thing. Internally double has more precision, but when you print a double it only prints with the amount of precision you need. The answer is to print the decimal with a format string as shown in the second line below. Double number = Double.parseDouble(“5.00000”); System.out.printf(“%.5f”, number); That second line says print a formatted string, % means print a variable, .5 means print 5 decimal places, f means the variable is floating point, and number is just the variable that stores your number. More on reddit.com

Without a code example, it's more or less impossible to debug. But before asking for help, I strongly suggest trying to figure this one out yourself. Think, what is the error message saying? What does that imply? More on reddit.com