diff --git a/Implementierung/main.c b/Implementierung/main.c
index 0c458ad..2733a2c 100644
--- a/Implementierung/main.c
+++ b/Implementierung/main.c
@@ -218,8 +218,11 @@ int main(int argc, char** argv)
         switch (opt_long)
         {
         case 'V': // done, function needed
-            version_to_use = strtol(optarg,NULL,10);
-            if (version_to_use < 0 || version_to_use > 5)
+            char *end;
+            version_to_use = strtol(optarg,&end,10);
+
+
+            if (version_to_use < 0 || version_to_use > 5 || end == optarg || *end != '\0')
             {
                 fprintf(stderr,"Invalid version to use: V%d. Available versions are : V0,V1,V2,V3,V4,V5\n", version_to_use);
                 return EXIT_FAILURE;
@@ -232,12 +235,14 @@ int main(int argc, char** argv)
             // gesetzt wird, soll ebenfalls die Hauptimplementierung ausgeführt werden
             break;
         
-        case 'B': // done, function needed
+        case 'B': { // done, function needed
             // wird die Laufzeit der angegebenen Implementierung gemessen und ausgegeben (do this later)
-            amount_function_called = strtol(optarg,NULL,10);
-            if (amount_function_called <= 0) {
+            char *end;
+            amount_function_called = strtol(optarg,&end,10);
+
+            if (amount_function_called <= 0 || end == optarg || *end != '\0') {
                 fprintf(stderr, "Invalid benchmarking input, the value should be greater than 0\n");
-                return 1;
+                return EXIT_FAILURE;
             }
             will_benchmark = true;
             printf("amount function called is %d\n", amount_function_called);
@@ -245,6 +250,7 @@ int main(int argc, char** argv)
 
             // Das Argument dieser Option gibt die Anzahl an Wiederholungen des Funktionsaufrufs an, z. B.-B 5 .
             break;
+        }
 
         case 's': {
             sGiven = true;
@@ -296,18 +302,27 @@ int main(int argc, char** argv)
             break;
         }
 
-        case 'n':
+        case 'n': {
             nGiven = true;
-            n = strtol(optarg,NULL,10);
+            char* end;
+            n = strtol(optarg,&end,10);
+
+            if (end == optarg || *end != '\0' || n <= 0)
+            {
+                fprintf(stderr, "Invalid n value: %s\n", optarg);
+                return EXIT_FAILURE;
+            }
+            
             printf("n:%d\n",n);
             // -n <Zahl> —MaximaleAnzahlanIterationen pro Bildpixel 
             break;
+        }
 
         case 'r': {
             rGiven = true;
             char *end;
             resolution = strtof(optarg,&end);
-            if (end == optarg || *end != '\0') 
+            if (end == optarg || *end != '\0' || resolution <= 0.0f) 
             {
                 fprintf(stderr, "Invalid floating point number: %s\n",optarg);
                 return EXIT_FAILURE;
@@ -319,7 +334,19 @@ int main(int argc, char** argv)
 
         case 'o':
             oGiven = true;
+            if (optarg[0] == '-')
+            {
+                fprintf(stderr, "Invalid output filename: %s\n",optarg);
+                return EXIT_FAILURE;
+            }
+            
             output_data = malloc(strlen(optarg) + 1);
+            if (output_data == NULL)
+            {
+                fprintf(stderr,"Memory allocation failed.\n");
+                return EXIT_FAILURE;
+            }
+            
             strcpy(output_data,optarg);
             printf("output data: %s\n", output_data); // test
             // -o <Dateiname> —Ausgabedatei
@@ -373,6 +400,8 @@ int main(int argc, char** argv)
     if (!(nGiven && rGiven && oGiven && dGiven && sGiven))
     {
         checkInputs(nGiven,rGiven,oGiven,dGiven,sGiven);
+        free(tempArr);
+        free(output_data);
         return EXIT_FAILURE;
     }
 
@@ -382,7 +411,7 @@ int main(int argc, char** argv)
         benchmarking(amount_function_called,version_to_use,complexA,width,height,resolution,n,colored,tempArr);
         free(tempArr);
         free(output_data);
-        return 0;
+        return EXIT_SUCCESS;
     }
     
     switch (version_to_use)