20) String Builder and String Formatting

public class Main {

    public static void main(String[] args) {

        //inefficient as it creates a new string location in memory each time you "add" to the original
        String info = "";

        info += "My name is Bob.";
        info += " ";
        info += "I am a builder.";

        System.out.println(info);


        //more efficient, as it edits the original rather than creating new instances of the variable
        StringBuilder sb = new StringBuilder("");

        sb.append("My name is Sue.");
        sb.append(" ");
        sb.append("I am a lion tamer.");

        System.out.println((sb.toString()));


        StringBuilder s = new StringBuilder();

        s.append("My name is Rodger.")
        .append(" ")
        .append("I am a skydiver.");

        System.out.println((s.toString()));

        // Formatting ///
        System.out.println("Here is some text.\tThat was a tab.\nThat was a new line.");

        //formatting characters allow more control
        System.out.printf("Total cost %-10d; quantity is %d\n", 5, 120);

        for(int i=0; i<20; i++){
            System.out.printf("%-2d: %s\n", i, "Here is some text");
        }

        //formatting floating point values
        System.out.printf("Total value: %.2f\n", 5.68784);
        System.out.printf("Total value: %10.2f\n", 343.47649);

    }
}