PrintStream printf(String, Object) method in Java with Examples

The printf(String, Object) method of PrintStream Class in Java is used to print a formatted string in the stream. The string is formatted using specified format and arguments passed as the parameter. Syntax:

public PrintStream printf(String format, Object...args)

Parameters: This method accepts two mandatory parameter:

• format which is the format according to which the String is to be formatted.
• args which is the number of arguments for the formatted string. It can be optional, i.e. no arguments or any number of arguments according to the format.

Return Value: This method returns this PrintStream instance. Exception: This method throws following exceptions:

• NullPointerException This is thrown if the format is null.
• IllegalFormatException This is thrown if the format specified is illegal or there are insufficient arguments.

Below methods illustrates the working of printf(String, Object) method: Program 1:

Java

// Java program to demonstrate
// PrintStream printf(String, Object) method

import java.io.*;

class GFG {
    public static void main(String[] args)
    {

        try {

            // Get the parameters
            double arg = 47.65734;

            String format = "GeeksForGeeks %.8f";

            // Create a PrintStream instance
            PrintStream stream
                = new PrintStream(System.out);

            // print the formatted string
            // to this stream using printf() method
            stream.printf(format, arg);

            stream.flush();
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

Output:

GeeksForGeeks 47.65734000

Program 2:

Java

// Java program to demonstrate
// PrintStream printf(String, Object) method

import java.io.*;

class GFG {
    public static void main(String[] args)
    {

        try {

            // Get the parameters

            String arg1 = "GFG";
            String arg2 = "GeeksforGeeks";

            String format = "A Computer Science "
                            + "Portal  %1$s, %1$s and %2$s";

            // Create a PrintStream instance
            PrintStream stream
                = new PrintStream(System.out);

            // print the formatted string
            // to this stream using printf() method
            stream.printf(format, arg1, arg2);

            stream.flush();
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

Output:

A Computer Science Portal  GFG, GFG and GeeksforGeeks

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