Below is the syntax highlighted version of Perimeter.java.
/* read integers xA, yA, xB, yB from stdin * print perimeter of triangle with corners * O=(0, 0), A=(xA, yA), B=(xB, yB) * * E.g.: if run with input 0 3 4 0, outputs 12.0 * visualization: http://goo.gl/bSZoVH */ public class Perimeter { // compute square public static int sqr(int x) { return x * x; } // compute distance of (x, y) from origin public static double hypot(int x, int y) { double sum = sqr(x); sum += sqr(y); return Math.sqrt(sum); } // first method to execute public static void main(String[] args) { int xA = StdIn.readInt(); int yA = StdIn.readInt(); int xB = StdIn.readInt(); int yB = StdIn.readInt(); double perim = 0; perim += hypot(xA-xB, yA-yB); // length of side AB perim += hypot(xA, yA); // length of side OA perim += hypot(xB, yB); // length of side OB StdOut.println(perim); } }