Method join

Skay_Exp/src/tools/Strings.java:10–21

(Iterable<String> strings, String sep, String prefix, String suffix)

public class Strings {
    public static String join(Iterable<String> strings, String sep, String prefix, String suffix) {
        final StringBuilder sb = new StringBuilder();
        boolean first = true;
        for (String s : strings) {
            if (! first) sb.append(sep);
            if (prefix != null) sb.append(prefix);
            sb.append(s);
            if (suffix != null) sb.append(suffix);
            first = false;
        }
        return sb.toString();
    }

    public static String repeat(String str, int num) {
        final String[] strs = new String[num];