Add exercises for pointers and const.

07_zeiger_const/callByReference.c

@@ -0,0 +1,60 @@
+/*
+ * Was gibt folgendes Programm aus? Erst überlegen, dann ausführen.
+ *
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#define MAX_TEXT_LEN 100
+
+typedef struct
+{
+    char text1[MAX_TEXT_LEN];
+    char *text2;
+    int number;
+} MyStruct;
+
+void modify1(MyStruct arg);
+void modify2(MyStruct *arg);
+
+int main()
+{
+    char text[MAX_TEXT_LEN] = "Text 2";
+    MyStruct someStruct = {"Text 1", text, 15};
+    
+    printf("someStruct.text1  = %s\n", someStruct.text1);
+    printf("someStruct.text2  = %s\n", someStruct.text2);
+    printf("someStruct.number = %d\n", someStruct.number);
+
+    modify1(someStruct);
+
+    printf("\nNach modify1:\n");
+    printf("someStruct.text1  = %s\n", someStruct.text1);
+    printf("someStruct.text2  = %s\n", someStruct.text2);
+    printf("someStruct.number = %d\n", someStruct.number);
+
+    modify2(&someStruct);
+
+    printf("\nNach modify2:\n");
+    printf("someStruct.text1  = %s\n", someStruct.text1);
+    printf("someStruct.text2  = %s\n", someStruct.text2);
+    printf("someStruct.number = %d\n", someStruct.number);
+
+    return EXIT_SUCCESS;
+}
+
+void modify1(MyStruct arg)
+{
+    strcpy(arg.text1, "Neuer Text 1");
+    strcpy(arg.text2, "Neuer Text 2");
+    arg.number = 100;
+}
+
+void modify2(MyStruct *arg)
+{
+    strcpy(arg->text1, "Wieder neuer Text 1");
+    strcpy(arg->text2, "Wieder neuer Text 2");
+    arg->number = 200;
+}