add 4

src/part4/aufg4.java

@@ -0,0 +1,31 @@
+package part4;
+
+import static java.lang.Math.round;
+
+public class aufg4 {
+    public static void main(String[] args){
+        int start = 5000;
+        int time = 20;
+        double interest1 = 1.01; //weird bug if these are floats
+        double interest2 = 1.02;
+        double interest3 = 1.04;
+
+        double start1 = start;
+        double start2 = start;
+        double start3 = start;
+
+        for(int i=0; i<time; i++){
+            start1 *= interest1;
+            start2 *= interest2;
+            start3 *= interest3;
+
+            System.out.println("after " + i + "times of " + round((interest1-1)*100) + "% interest  " + start1);
+            System.out.println("after " + i + "times of " + round((interest2-1)*100) + "% interest  " + start2);
+            System.out.println("after " + i + "times of " + round((interest3-1)*100) + "% interest  " + start3);
+
+            System.out.println();
+            System.out.println("=======================================");
+            System.out.println();
+        }
+    }
+}