Javakurs/Übungsaufgaben/Rekursion vs. Iteration/Musterlösung - Versionsgeschichte

MarkusH: fix alignment

2013-03-04T13:41:37Z

fix alignment

Jörg F: hat „Javakurs2007/Rekursion vs. Iteration/Musterlösung“ nach „Javakurs/Übungsaufgaben/Rekursion vs. Iteration/Musterlösung“ verschoben

2010-08-01T12:04:19Z

hat „Javakurs2007/Rekursion vs. Iteration/Musterlösung“ nach „Javakurs/Übungsaufgaben/Rekursion vs. Iteration/Musterlösung“ verschoben

130.149.24.73: Die Seite wurde neu angelegt: „

 public class RekursionVsIteration {    public static void main( String args[] ) {      int[] testValues= {5, 10, 15, 20, 30, 40};     timeTest( testValues);...“

2010-03-22T11:28:15Z

Die Seite wurde neu angelegt: „<pre> public class RekursionVsIteration { public static void main( String args[] ) { int[] testValues= {5, 10, 15, 20, 30, 40}; timeTest( testValues);...“

Neue Seite

<pre>
public class RekursionVsIteration {

public static void main( String args[] ) {

int[] testValues= {5, 10, 15, 20, 30, 40};
timeTest( testValues);

}

/* calculates FibonacciNumbers */
public static int fibonacciRek( int n ) {

int result;

if (n <= 1) {
if (n == 1) {
result = 1;
} else if (n == 0) {
result= 0;
} else {
System.out.println("Fibonacci numbers undefined for "+
"negative values." );
result = -1;
}
} else {
result= fibonacciRek(n - 1) + fibonacciRek(n - 2);
}
return result;
}

public static int fibonacciIte (int n) {

int result;

if (n <= 1) {
if (n == 1) {
result = 1;
} else if (n == 0) {
result= 0;
} else {
System.out.println("Fibonacci numbers undefined for "+
"negative values." );
result = -1;
}
} else {

/* n+1 because in the n-th entry is the n-th
* fibonacci number */
int[] predecessors= new int[n+1];

predecessors[0]= 0;
predecessors[1]= 1;

for ( int i= 2; i < predecessors.length; i++ ) {
predecessors[i]= predecessors[i-1] + predecessors[i-2];
}

result= predecessors[n];
}

return result;
}

public static void timeTest(int[] values){
long before;
long after;

/*recursion time test*/
before = System.currentTimeMillis();

for ( int i=0; i< values.length; i++) {

// fibonacciRek(values[i]);
System.out.print("f(" +values[i] + ")= ");
System.out.println( fibonacciRek(values[i]) );
}

after = System.currentTimeMillis();
System.out.println("Rekursion benötigt: " + (after - before) + " ms");

/*iteration time test*/
before = System.currentTimeMillis();

for ( int i=0; i< values.length; i++) {
// fibonacciIte(values[i]);
System.out.print("f(" +values[i] + ")= ");
System.out.println( fibonacciIte(values[i]) );
}

after = System.currentTimeMillis();
System.out.println("Iteration benötigt: " + (after - before) + " ms");

}

}
</pre>

@@ Zeile 1: / Zeile 1: @@
 <pre>
-public class RekursionVsIteration {
+public class RecursionVsIteration {
-  public static void main( String args[] ) {
+	/* calculates FibonacciNumbers */
-    int[] testValues= {5, 10, 15, 20, 30, 40};
+	public static int fibonacciIte(int n) {
-    timeTest( testValues);
+		int result;
+	public static void timeTest(int[] values) {
+		long before;
-  /* calculates FibonacciNumbers */
+		long after;
-  public static int fibonacciRek( int n ) {
+		// recursion time test
+		before = System.currentTimeMillis();
-    int result;
+		for (int i = 0; i < values.length; i++) {
+			// fibonacciRek(values[i]);
-    if (n <= 1) {
+			System.out.print("f(" + values[i] + ")= ");
-       if (n == 1) {
+			System.out.println(fibonacciRek(values[i]));
-          result = 1;
-       } else if (n == 0) {
+		after = System.currentTimeMillis();
-          result= 0;
+		System.out.println("Rekursion benötigt: " + (after - before) + " ms");
-       } else {
+		// iteration time test
-          System.out.println("Fibonacci numbers undefined for "+
+		before = System.currentTimeMillis();
+}
 </pre>

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