DEV3.2 TP'S

DEV/DEV3.2/TP02/Exercise1/Recursion.java

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+public class Recursion {
+    
+    public static void main(String[] args) {
+        if(args.length > 0) {
+            displayFactorial(Integer.parseInt(args[0]));
+            return; 
+        }
+
+        System.out.println("Usage: java Recursion <number>");
+    }
+
+    public static void displayFactorial(int n) {
+        System.out.println(n + "! = " + factorial(n, 0));
+    }
+
+    private static int factorial(int n, int count) {
+        count++;
+        System.out.println("n = " + n + " | count = " + count);
+
+        if(n == 0) {
+            //Thread.dumpStack();
+            return 1; 
+        }
+
+        return n * factorial(n - 1, count);
+    }
+}

DEV/DEV3.2/TP02/Exercise1/answer.txt

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+Avec utilisation de dumpStack() : 
+On test pour factoriel de 3, on y voit bien 4 appels : 
+- 3 qui appellent le cas réussit 
+- 1 qui appelle le cas de base 
+
+nathanpasdutout@Macbook-Air-Nathan Exercise1 % java Recursion 3    
+java.lang.Exception: Stack trace
+        at java.base/java.lang.Thread.dumpStack(Thread.java:2209)
+        at Recursion.factorial(Recursion.java:18)
+        at Recursion.factorial(Recursion.java:22)
+        at Recursion.factorial(Recursion.java:22)
+        at Recursion.factorial(Recursion.java:22)
+        at Recursion.displayFactorial(Recursion.java:13)
+        at Recursion.main(Recursion.java:5)

DEV/DEV3.2/TP02/Exercise2/ArrayRecursion.java

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+public class ArrayRecursion {
+    
+    public static void main(String[] args) {
+        displayNumberOfPaireNumber(convertCommandArray(args));
+    }
+
+    public static int[] convertCommandArray(String[] args) {
+        return convertArray(args, 0, new int[args.length]);
+    }
+
+    private static int[] convertArray(String[] args, int index, int[] integerArray) {
+        if(index >= args.length) {
+            return integerArray; 
+        }
+
+        integerArray[index] = Integer.parseInt(args[index]);
+        return convertArray(args, index + 1, integerArray);
+    }
+
+    public static void displayNumberOfPaireNumber(int[] array) {
+        System.out.println("Nombre de nombres paires : " + getNumberOfPaireNumber(array, 0));
+    }
+
+    private static int getNumberOfPaireNumber(int[] array, int index) {
+        if(index >= array.length) {
+            return 0;
+        }
+
+        if(array[index] % 2 == 0) {
+            return getNumberOfPaireNumber(array, index + 1) + 1; 
+        }
+
+        return getNumberOfPaireNumber(array, index + 1);
+    }
+}