CDE

Task/Euler-method/Java/euler-method.java

@@ -0,0 +1,33 @@
+public class Euler {
+  private static void euler (Callable f, double y0, int a, int b, int h) {
+    int t = a;
+    double y = y0;
+    while (t < b) {
+      System.out.println ("" + t + " " + y);
+      t += h;
+      y += h * f.compute (t, y);
+    }
+    System.out.println ("DONE");
+  }
+
+  public static void main (String[] args) {
+    Callable cooling = new Cooling ();
+    int[] steps = {2, 5, 10};
+    for (int stepSize : steps) {
+      System.out.println ("Step size: " + stepSize);
+      euler (cooling, 100.0, 0, 100, stepSize);
+    }
+  }
+}
+
+// interface used so we can plug in alternative functions to Euler
+interface Callable {
+  public double compute (int time, double t);
+}
+
+// class to implement the newton cooling equation
+class Cooling implements Callable {
+  public double compute (int time, double t) {
+    return -0.07 * (t - 20);
+  }
+}