How to Enter a Float Literal in Java

Java programs can take a wide variety of keyboard user inputs. You can enter strings and any primitive numerical type: integer, long, float or double (double-precision float). In principle, all console input is just a stream of uninterpreted bytes -- so you need to call the appropriate Java library functions to parse a particular input as a float. When the application executes, the user will provide that particular input by following Java's syntax rules for float literals (constant values).

Instructions

1. Include the following line at the beginning of your Java code:

   import java.io.*;

2. Write code that creates an instance of the pre-defined BufferedReader Java class to read input from the console, as in the following sample code:

   BufferedReader myInputStream = new BufferedReader(new InputStreamReader(System.in));

   "System.in" is the input stream defined for every Java application, also called "standard input."

3. Include code that reads a float number from the BufferedReader object:

   float myFloat;

   myFloat = Float.parseFloat(myInputStream.readLine());

4. Compile your whole Java application, including the code added in Steps 1 through 3, by clicking "Start," then typing "cmd" into the search box and pressing "Enter." A new Command line will open. Type the following command into it:

   javac myMainClass.java

   Replace "myMainClass.java" by the name of the file containing the source Java code. Press "Enter."

5. Execute your Java application by typing the following command into the Command window:

   java myMainClass.class

   Press "Enter."

6. Enter the float literal when your code prompts you for it by typing it as in the following example:

   2.71828

   Press "Enter." The Java program will parse the float literal and store its value into the variable "myFloat."

References

• Oracle: Java: Class Float