From a905d1e4ca0179518be914e10c2577313a4b4623 Mon Sep 17 00:00:00 2001
From: Peter Gerwinski <peter.gerwinski@hs-bochum.de>
Date: Mon, 16 Jan 2023 14:33:25 +0100
Subject: [PATCH] Notizen und Beispiele 16.1.2023
---
20230116/func-pointers-01.c | 12 +++++++++++
20230116/func-pointers-02.c | 18 +++++++++++++++++
20230116/func-pointers-03.c | 14 +++++++++++++
20230116/func-pointers-04.c | 23 +++++++++++++++++++++
20230116/func-pointers-05.c | 23 +++++++++++++++++++++
20230116/func-pointers-06.c | 26 ++++++++++++++++++++++++
20230116/func-pointers-07.c | 26 ++++++++++++++++++++++++
20230116/func-pointers-08.c | 36 +++++++++++++++++++++++++++++++++
20230116/func-pointers-09.c | 35 ++++++++++++++++++++++++++++++++
20230116/func-pointers-10.c | 34 +++++++++++++++++++++++++++++++
20230116/hp-20230116.txt | 19 +++++++++++++++++
20230116/pointers-01.c | 12 +++++++++++
20230116/pointers-01.pas | 12 +++++++++++
20230116/pointers-02.c | 12 +++++++++++
20230116/pointers-03.c | 15 ++++++++++++++
20230116/struct-pointers-01.c | 18 +++++++++++++++++
20230116/struct-pointers-02.c | 18 +++++++++++++++++
20230116/struct-pointers-03.c | 18 +++++++++++++++++
20230116/struct-pointers-03.pas | 17 ++++++++++++++++
20230116/struct-pointers-04.c | 17 ++++++++++++++++
20230116/struct-pointers-05.c | 17 ++++++++++++++++
21 files changed, 422 insertions(+)
create mode 100644 20230116/func-pointers-01.c
create mode 100644 20230116/func-pointers-02.c
create mode 100644 20230116/func-pointers-03.c
create mode 100644 20230116/func-pointers-04.c
create mode 100644 20230116/func-pointers-05.c
create mode 100644 20230116/func-pointers-06.c
create mode 100644 20230116/func-pointers-07.c
create mode 100644 20230116/func-pointers-08.c
create mode 100644 20230116/func-pointers-09.c
create mode 100644 20230116/func-pointers-10.c
create mode 100644 20230116/hp-20230116.txt
create mode 100644 20230116/pointers-01.c
create mode 100644 20230116/pointers-01.pas
create mode 100644 20230116/pointers-02.c
create mode 100644 20230116/pointers-03.c
create mode 100644 20230116/struct-pointers-01.c
create mode 100644 20230116/struct-pointers-02.c
create mode 100644 20230116/struct-pointers-03.c
create mode 100644 20230116/struct-pointers-03.pas
create mode 100644 20230116/struct-pointers-04.c
create mode 100644 20230116/struct-pointers-05.c
diff --git a/20230116/func-pointers-01.c b/20230116/func-pointers-01.c
new file mode 100644
index 0000000..b2db514
--- /dev/null
+++ b/20230116/func-pointers-01.c
@@ -0,0 +1,12 @@
+#include <stdio.h>
+
+void hello (void)
+{
+ printf ("Hello, world!\n");
+}
+
+int main (void)
+{
+ hello ();
+ return 0;
+}
diff --git a/20230116/func-pointers-02.c b/20230116/func-pointers-02.c
new file mode 100644
index 0000000..7c9d60e
--- /dev/null
+++ b/20230116/func-pointers-02.c
@@ -0,0 +1,18 @@
+#include <stdio.h>
+
+void hello (void)
+{
+ printf ("Hello, world!\n");
+}
+
+int main (void)
+{
+ /* h ist ein Zeiger auf eine Funktion;
+ h soll auf die Funktion hello() zeigen; */
+ /* Merken: "*h ist eine Funktion." */
+ /* void *h (void) wäre eine Funktion, die keine Parameter bekommt
+ und einen Zeiger auf void zurückgibt. */
+ void (*h) (void) = hello;
+ h ();
+ return 0;
+}
diff --git a/20230116/func-pointers-03.c b/20230116/func-pointers-03.c
new file mode 100644
index 0000000..003591a
--- /dev/null
+++ b/20230116/func-pointers-03.c
@@ -0,0 +1,14 @@
+#include <stdio.h>
+
+void hello (void)
+{
+ printf ("Hello, world!\n");
+}
+
+int main (void)
+{
+ typedef void (*funcptr) (void);
+ funcptr h = hello;
+ h ();
+ return 0;
+}
diff --git a/20230116/func-pointers-04.c b/20230116/func-pointers-04.c
new file mode 100644
index 0000000..403cb68
--- /dev/null
+++ b/20230116/func-pointers-04.c
@@ -0,0 +1,23 @@
+#include <stdio.h>
+
+typedef struct
+{
+ void (*greeting) (void); // Zeiger auf Funktion, nicht initialisiert
+}
+object;
+
+void hello (void)
+{
+ printf ("Hello, world!\n");
+}
+
+int main (void)
+{
+ object o;
+
+ o.greeting = hello; // "Konstruktor" - Initiallisieren des Funktions-Zeigers
+ //Ohne Klammerpaar: Adresse der Funktion
+ o.greeting (); // mit Klammerpaar: Funktion aufrufen
+
+ return 0;
+}
diff --git a/20230116/func-pointers-05.c b/20230116/func-pointers-05.c
new file mode 100644
index 0000000..8870230
--- /dev/null
+++ b/20230116/func-pointers-05.c
@@ -0,0 +1,23 @@
+#include <stdio.h>
+
+typedef struct
+{
+ void (*greeting) (void); // Zeiger auf Funktion, nicht initialisiert
+}
+object;
+
+void hello (void)
+{
+ printf ("Hello, world!\n");
+}
+
+int main (void)
+{
+ object *o;
+ // FEHLER: Verwendung von "o" ohne daß "o" auf etwas Sinnvolles zeigt!
+ o->greeting = hello; // "Konstruktor" - Initiallisieren des Funktions-Zeigers
+ // Ohne Klammerpaar: Adresse der Funktion
+ o->greeting (); // mit Klammerpaar: Funktion aufrufen
+
+ return 0;
+}
diff --git a/20230116/func-pointers-06.c b/20230116/func-pointers-06.c
new file mode 100644
index 0000000..995bc6e
--- /dev/null
+++ b/20230116/func-pointers-06.c
@@ -0,0 +1,26 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct
+{
+ void (*greeting) (void); // Zeiger auf Funktion, nicht initialisiert
+}
+object;
+
+void hello (void)
+{
+ printf ("Hello, world!\n");
+}
+
+int main (void)
+{
+ object *o;
+
+ o = malloc (sizeof (object)); // Speicherplatz dynamisch erzeugen
+
+ o->greeting = hello; // "Konstruktor" - Initiallisieren des Funktions-Zeigers
+ // Ohne Klammerpaar: Adresse der Funktion
+ o->greeting (); // mit Klammerpaar: Funktion aufrufen
+
+ return 0;
+}
diff --git a/20230116/func-pointers-07.c b/20230116/func-pointers-07.c
new file mode 100644
index 0000000..a47689d
--- /dev/null
+++ b/20230116/func-pointers-07.c
@@ -0,0 +1,26 @@
+#include <stdio.h>
+
+typedef struct
+{
+ void (*greeting) (void); // Zeiger auf Funktion, nicht initialisiert
+}
+object;
+
+void hello (void)
+{
+ printf ("Hello, world!\n");
+}
+
+int main (void)
+{
+ object *o;
+
+ object apfel; // Speicherplatz innerhalb von main() reservieren
+ o = &apfel; // Zeiger darauf zeigen lassen
+
+ o->greeting = hello; // "Konstruktor" - Initiallisieren des Funktions-Zeigers
+ // Ohne Klammerpaar: Adresse der Funktion
+ o->greeting (); // mit Klammerpaar: Funktion aufrufen
+
+ return 0;
+}
diff --git a/20230116/func-pointers-08.c b/20230116/func-pointers-08.c
new file mode 100644
index 0000000..0b28bed
--- /dev/null
+++ b/20230116/func-pointers-08.c
@@ -0,0 +1,36 @@
+#include <stdio.h>
+
+typedef struct
+{
+ void (*greeting) (void); // Zeiger auf Funktion, nicht initialisiert
+}
+object;
+
+void hello_apple (void)
+{
+ printf ("Hello, apple!\n");
+}
+
+void hello_pear (void)
+{
+ printf ("Hello, pear!\n");
+}
+
+int main (void)
+{
+ object *a;
+ object *b;
+
+ object apfel; // Speicherplatz innerhalb von main() reservieren
+ a = &apfel; // Zeiger darauf zeigen lassen
+ a->greeting = hello_apple; // "Konstruktor": virtuelle Methode initialisieren
+
+ object birne; // Speicherplatz innerhalb von main() reservieren
+ b = &birne; // Zeiger darauf zeigen lassen
+ b->greeting = hello_pear; // "Konstruktor": virtuelle Methode initialisieren
+
+ a->greeting ();
+ b->greeting ();
+
+ return 0;
+}
diff --git a/20230116/func-pointers-09.c b/20230116/func-pointers-09.c
new file mode 100644
index 0000000..25ca1bb
--- /dev/null
+++ b/20230116/func-pointers-09.c
@@ -0,0 +1,35 @@
+#include <stdio.h>
+
+typedef struct
+{
+ void (*greeting) (void); // Zeiger auf Funktion, nicht initialisiert
+}
+object;
+
+void hello_apple (void)
+{
+ printf ("Hello, apple!\n");
+}
+
+void hello_pear (void)
+{
+ printf ("Hello, pear!\n");
+}
+
+int main (void)
+{
+ object *o[2]; // Array mit 2 Zeigern auf Objekte
+
+ object apfel; // Speicherplatz innerhalb von main() reservieren
+ o[0] = &apfel; // Zeiger darauf zeigen lassen
+ o[0]->greeting = hello_apple; // "Konstruktor": virtuelle Methode initialisieren
+
+ object birne; // Speicherplatz innerhalb von main() reservieren
+ o[1] = &birne; // Zeiger darauf zeigen lassen
+ o[1]->greeting = hello_pear; // "Konstruktor": virtuelle Methode initialisieren
+
+ for (int i = 0; i < 2; i++)
+ o[i]->greeting ();
+
+ return 0;
+}
diff --git a/20230116/func-pointers-10.c b/20230116/func-pointers-10.c
new file mode 100644
index 0000000..10ad166
--- /dev/null
+++ b/20230116/func-pointers-10.c
@@ -0,0 +1,34 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct
+{
+ void (*greeting) (void); // Zeiger auf Funktion, nicht initialisiert
+}
+object;
+
+void hello_apple (void)
+{
+ printf ("Hello, apple!\n");
+}
+
+void hello_pear (void)
+{
+ printf ("Hello, pear!\n");
+}
+
+int main (void)
+{
+ object *o[2]; // Array mit 2 Zeigern auf Objekte
+
+ o[0] = malloc (sizeof (object)); // "Konstrutor": Speicherplatz dynamisch reservieren
+ o[0]->greeting = hello_apple; // "Konstruktor": virtuelle Methode initialisieren
+
+ o[1] = malloc (sizeof (object)); // "Konstrutor": Speicherplatz dynamisch reservieren
+ o[1]->greeting = hello_pear; // "Konstruktor": virtuelle Methode initialisieren
+
+ for (int i = 0; i < 2; i++)
+ o[i]->greeting ();
+
+ return 0;
+}
diff --git a/20230116/hp-20230116.txt b/20230116/hp-20230116.txt
new file mode 100644
index 0000000..d53358e
--- /dev/null
+++ b/20230116/hp-20230116.txt
@@ -0,0 +1,19 @@
+Klausur-Themen, 16.01.2023, 13:57:20
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ - Seiteneffekte
+ - Arrays, Zeiger, Strings
+ - Speicherzellen
+ - Bit-Manipulation
+ - Endianness
+ - Alignment
+ - Algorithmen, Landau-Symbol
+ - Objekte, Zeiger auf Funktionen
+
+--> Es ist mal wieder Zeit für:
+ - Seiteneffekte
+ - Mikrocontroller
+
+Zeiger, 16.01.2023, 11:30:23
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ - auf Funktionen
+ - auf Structs und Unions
diff --git a/20230116/pointers-01.c b/20230116/pointers-01.c
new file mode 100644
index 0000000..230e8ed
--- /dev/null
+++ b/20230116/pointers-01.c
@@ -0,0 +1,12 @@
+#include <stdio.h>
+
+int main (void)
+{
+ int a = 7;
+ int b = 13;
+ int *p = &a;
+ printf ("*p = %d\n", *p);
+ p = &b;
+ printf ("*p = %d\n", *p);
+ return 0;
+}
diff --git a/20230116/pointers-01.pas b/20230116/pointers-01.pas
new file mode 100644
index 0000000..1fe7afc
--- /dev/null
+++ b/20230116/pointers-01.pas
@@ -0,0 +1,12 @@
+program Pointers;
+
+var
+ a: Integer = 7;
+ b: Integer = 13;
+ p: ^Integer = @a;
+
+begin
+ WriteLn ('p^ = ', p^);
+ p := @b;
+ WriteLn ('p^ = ', p^)
+end.
diff --git a/20230116/pointers-02.c b/20230116/pointers-02.c
new file mode 100644
index 0000000..b551c9c
--- /dev/null
+++ b/20230116/pointers-02.c
@@ -0,0 +1,12 @@
+#include <stdio.h>
+
+int main (void)
+{
+ int a = 7;
+ int b = 13;
+ int *p = &a;
+ printf ("*p = %d\n", *p);
+ *p = &b; /* falsch */
+ printf ("*p = %d\n", *p);
+ return 0;
+}
diff --git a/20230116/pointers-03.c b/20230116/pointers-03.c
new file mode 100644
index 0000000..b330a5f
--- /dev/null
+++ b/20230116/pointers-03.c
@@ -0,0 +1,15 @@
+#include <stdio.h>
+
+int main (void)
+{
+ int a = 7;
+ int b = 13;
+ int *p;
+ p = &a;
+ printf ("*p = %d\n", *p);
+ *p = &b; /* falsch: Zuweisung der Speicheradresse von b an die Zahl a,
+ weil p zu diesem Zeitpunkt auf a zeigt */
+ printf ("*p = %d\n", *p);
+ printf ("a = %d\n", a);
+ return 0;
+}
diff --git a/20230116/struct-pointers-01.c b/20230116/struct-pointers-01.c
new file mode 100644
index 0000000..9837cbf
--- /dev/null
+++ b/20230116/struct-pointers-01.c
@@ -0,0 +1,18 @@
+#include <stdio.h>
+
+typedef struct
+{
+ int a;
+ int b;
+}
+data;
+
+int main (void)
+{
+ data d;
+ d.a = 7;
+ d.b = 13;
+ data *p = &d;
+ printf ("*p = { %d, %d }\n", *p.a, *p.b);
+ return 0;
+}
diff --git a/20230116/struct-pointers-02.c b/20230116/struct-pointers-02.c
new file mode 100644
index 0000000..d6527ad
--- /dev/null
+++ b/20230116/struct-pointers-02.c
@@ -0,0 +1,18 @@
+#include <stdio.h>
+
+typedef struct
+{
+ int a;
+ int b;
+}
+data;
+
+int main (void)
+{
+ data d;
+ d.a = 7;
+ d.b = 13;
+ data *p = &d;
+ printf ("*p = { %d, %d }\n", (*p).a, (*p).b);
+ return 0;
+}
diff --git a/20230116/struct-pointers-03.c b/20230116/struct-pointers-03.c
new file mode 100644
index 0000000..2aebb06
--- /dev/null
+++ b/20230116/struct-pointers-03.c
@@ -0,0 +1,18 @@
+#include <stdio.h>
+
+typedef struct
+{
+ int a;
+ int b;
+}
+data;
+
+int main (void)
+{
+ data d;
+ d.a = 7;
+ d.b = 13;
+ data *p = &d;
+ printf ("*p = { %d, %d }\n", p->a, p->b);
+ return 0;
+}
diff --git a/20230116/struct-pointers-03.pas b/20230116/struct-pointers-03.pas
new file mode 100644
index 0000000..2c998ff
--- /dev/null
+++ b/20230116/struct-pointers-03.pas
@@ -0,0 +1,17 @@
+program StructPointers;
+
+type
+ data = record
+ a, b: Integer
+ end;
+
+var
+ d: data;
+ p: ^data;
+
+begin
+ d.a := 7;
+ d.b := 13;
+ p := @d;
+ WriteLn ('p^ = { ', p^.a, ', ', p^.b, ' }')
+end.
diff --git a/20230116/struct-pointers-04.c b/20230116/struct-pointers-04.c
new file mode 100644
index 0000000..ca2c30c
--- /dev/null
+++ b/20230116/struct-pointers-04.c
@@ -0,0 +1,17 @@
+#include <stdio.h>
+
+typedef struct
+{
+ int a;
+ int b;
+}
+data;
+
+int main (void)
+{
+ data d;
+ d.a = 7;
+ d.b = 13;
+ printf ("d = { %d, %d }\n", d->a, d->b);
+ return 0;
+}
diff --git a/20230116/struct-pointers-05.c b/20230116/struct-pointers-05.c
new file mode 100644
index 0000000..d98b8f2
--- /dev/null
+++ b/20230116/struct-pointers-05.c
@@ -0,0 +1,17 @@
+#include <stdio.h>
+
+typedef struct
+{
+ int a;
+ int b;
+}
+data;
+
+int main (void)
+{
+ data d;
+ d.a = 7;
+ d.b = 13;
+ printf ("d = { %d, %d }\n", d.a, d.b);
+ return 0;
+}
--
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