The goal of this post is to show how to match words and replace them in a string using java. We are looking for words of three characters that start with a lower case letter and are followed by two digits. It took me a while to remember about the word boundaries (those represented by \\b). Pay attention to that. By the way, this exercise I found on the book Competitive Programming....
One way to evaluate simple math expressions in Java just takes a couple lines of code. It uses Javascript’s engine to do that and it is quite useful. // to use eval import javax.script.ScriptEngineManager; import javax.script.ScriptEngine; // to use scanner import java.util.*; class Main { public static void main(String[] args) throws Exception { ScriptEngineManager mgr; mgr = new ScriptEngineManager(); ScriptEngine engine; engine = mgr.getEngineByName("JavaScript"); Scanner scan = new Scanner(System.in); String foo = scan....
There are some details I never cared about that I started to learn. One of them is just printing to the screen with variable precision. The solution is quite simple. import java.util.*; /** * Prints pi with n decimal places. * n is given by the user */ class Main { public static void main(String[] args) { double pi = Math.PI; Scanner scanner = new Scanner(System.in); int precision = scanner.nextInt(); scanner....