Java Print Numbers - Complete Guide
Printing Numbers in Java
Printing numbers requires understanding how to format numerical data for clear and readable output.
You can display all numeric types such as int, double, float, and long. Java also supports calculations directly inside output statements.
Basic Number Printing
The simplest way to print numbers is by concatenating them with strings or directly passing them to output methods.
Example
public class NumberPrinting {
public static void main(String[] args) {
int age = 25;
double price = 19.99;
float temperature = 98.6f;
long population = 7800000000L;
// Basic number printing
System.out.println("Age: " + age);
System.out.println("Price: " + price);
System.out.println("Temperature: " + temperature);
System.out.println("World Population: " + population);
// Inline calculations
int x = 10, y = 20;
System.out.println("Sum: " + (x + y));
System.out.println("Product: " + (x * y));
System.out.println("Average: " + ((x + y) / 2.0));
}
}Output
Age: 25 Price: 19.99 Temperature: 98.6 World Population: 7800000000 Sum: 30 Product: 200 Average: 15.0
Number Formatting with printf
For precise control, printf supports format specifiers for decimals, integers, padding, and more.
Example
public class NumberFormatting {
public static void main(String[] args) {
double value = 12345.6789;
// Floating-point formats
System.out.printf("Default: %f%n", value);
System.out.printf("Two decimals: %.2f%n", value);
System.out.printf("No decimals: %.0f%n", value);
System.out.printf("With commas: %,f%n", value);
System.out.printf("Scientific: %e%n", value);
// Integer formats
int number = 42;
System.out.printf("Decimal: %d%n", number);
System.out.printf("Octal: %o%n", number);
System.out.printf("Hexadecimal: %x%n", number);
System.out.printf("Padded: %05d%n", number);
// Currency-like formatting
double amount = 1234.567;
System.out.printf("Currency: $%,.2f%n", amount);
}
}Output
Default: 12345.678900 Two decimals: 12345.68 No decimals: 12346 With commas: 12,345.678900 Scientific: 1.234568e+04 Decimal: 42 Octal: 52 Hexadecimal: 2a Padded: 00042 Currency: $1,234.57
Advanced Number Display
For more advanced formatting, Java provides NumberFormat and DecimalFormat for locale-specific and custom patterns.
Example
import java.text.NumberFormat;
import java.text.DecimalFormat;
import java.util.Locale;
public class AdvancedFormatting {
public static void main(String[] args) {
double number = 1234567.8912;
// Locale-based formatting
NumberFormat usFormat = NumberFormat.getInstance(Locale.US);
NumberFormat frFormat = NumberFormat.getInstance(Locale.FRANCE);
System.out.println("US Format: " + usFormat.format(number));
System.out.println("French Format: " + frFormat.format(number));
// Currency formatting
NumberFormat currency = NumberFormat.getCurrencyInstance(Locale.US);
System.out.println("US Currency: " + currency.format(number));
// Custom patterns
DecimalFormat customFormat = new DecimalFormat("###,###.###");
System.out.println("Custom Format: " + customFormat.format(number));
DecimalFormat percentFormat = new DecimalFormat("##.##%");
System.out.println("Percentage: " + percentFormat.format(0.856));
}
}Output
US Format: 1,234,567.891 French Format: 1 234 567,891 US Currency: $1,234,567.89 Custom Format: 1,234,567.891 Percentage: 85.6%