How to Use Java printf with Variable Field Sizes?

How can I use variable field sizes in Java's printf function?

int width = 10;
String name = "Alice";
System.out.printf("%s%ndays%n", String.format("%" + width + "s", name));

In Java, the `printf` method provides a way to print formatted output using specification strings. When you need to use variable field sizes, you can build the format string dynamically using the `String.format` method combined with `printf` for effective formatting.

int width = 15;
String name = "Alice";
// Creating dynamic format string
String formatString = String.format("%%%ds", width);
System.out.printf(formatString, name); // This prints '        Alice' with 15 total spaces.

Causes

• Fixed field sizes do not provide flexibility for dynamic data length.
• Using hardcoded values limits adaptability in applications.

Solutions

• Use `String.format` to create a dynamic format string with variable widths.
• Combine both `String.format` and `System.out.printf` to achieve the desired output.

Mistake: Not using the correct placeholder for the variable length.

Solution: Make sure to concatenate the field size with the format specifier using `String.format`.

Mistake: Hardcoding field sizes instead of using variables.

Solution: Define field sizes as variables to provide flexibility in formatting.