refactor various files

S1/GdCP/uebung/code.c

@@ -0,0 +1,22 @@
+#include<string.h>
+#include<ctype.h>
+
+char* convert_message(const char *message, char receiver) {
+  char *out = strdup(message);
+  if (receiver != 'M' && receiver != 'L') return "Mit dir schreib ich nicht!";
+  int c = 0;
+  for (int i = 0; message[i] != '\0'; i++) {
+    if (isalpha(message[i])) {
+      if (receiver == 'M') {
+        if (c % 2 == 1) out[i] = toupper(message[i]);
+        else out[i] = tolower(message[i]);
+        }
+      else {
+        if (c % 2 == 0) out[i] = toupper(message[i]);
+        else out[i] = tolower(message[i]);
+      }
+      c++;
+    }
+  }
+  return out;
+}