diff --git a/src/CustomerData.txt b/src/CustomerData.txt
index b4ef5a9..85c885c 100644
--- a/src/CustomerData.txt
+++ b/src/CustomerData.txt
@@ -3,6 +3,4 @@ ID=1234
 forename=Max
 Surname=Mustermann
 password=example
-balance=0
-
-
+balance=0
\ No newline at end of file
diff --git a/src/mainMenu.c b/src/mainMenu.c
index 163dacf..f0c45eb 100644
--- a/src/mainMenu.c
+++ b/src/mainMenu.c
@@ -25,16 +25,7 @@ bool checkIfInteger(char* userInput)
 bool chooseOption(int choiceInput)
 {
 
-    if(choiceInput<1 || choiceInput>4)
-    {
-        return false;
-    }
-
-    else
-    {
-
-        return true;
-    }
+    return !(choiceInput < 1 || choiceInput > 4);
 
 }
 
@@ -55,148 +46,82 @@ void ageInput()
 
     while (true)
     {
-	age = strtol(userInput,&userInputPointer,10);
-
-        if((checkIfInteger(userInput))&& (agePermission(age)))
-	{
+	    /*the userInput string is changed to a number with the strtol function*/
 
-	    printf("Access granted!\n\n\n\n");
+	    age = strtol(userInput,&userInputPointer,10);
 
-	    showMenu();
-             
-            menuInput();
+        if((checkIfInteger(userInput))&& (agePermission(age)))
+	    {
 
+	        printf("Access granted!\n\n\n\n");
+	        showMenu();
             menuInput();
+	        break;
+    	}
 
-	    break;
-
-	}
-
-	else if((checkIfInteger(userInput)) && !(agePermission(age))) 
-	{
+	    else if((checkIfInteger(userInput)) && !(agePermission(age))) 
+	    {
 
             printf("You should be at least 18 years old to create a bank account!\n");
 
-	    break;
-
-	}
+	        break;
 
-	else
-	{
-	    printf("input invalid! try again!\n");
-        scanf("%s",userInput);
+	    }
 
-	}
-    
-    }
-
-}
-void menuInput()
-{
-
-    char choiceInput[20];
-
-    char* choiceInputPointer;
-
-    int selection;
-    
-    scanf("%s",choiceInput);
-    
-    while(true)
-    {
-        selection = strtol(choiceInput,&choiceInputPointer,10);
-
-        if(chooseOption(selection) == true && checkIfInteger(choiceInput) == true)
-	{
-            switch(selection)
+	    else
 	    {
+	        printf("input invalid! try again!\n");
+            scanf("%s",userInput);
+            int c;
+            /*this loop flushes the input buffer for the upcoming getchar*/
+            while ((c = getchar()) != '\n' && c != EOF) {};
 
-                case 1 : printf("\nLoginAsCostumer() function will be implemented here soon\n\n");
-
-                         break;
-
-                case 2 : printf("\ncreateCostumerAccount() function will be implemented here soon\n\n");
-
-                         break;
-
-                case 3 : printf("\nLoginAsEmployee() function will be implemented here soon\n\n");
-
-                         break;
-
-                case 4 : printf("\e[1;1H\e[2J");
-
-			 printf("\nsee you next time !\n\n");
-
-                         break;
-                
-             }
-	    break;
-        }
-
-        else
-        {
-            printf("Input invalid! try again!\n");
-
-	    scanf("%s",choiceInput);
-        }
+	    }
+    
     }
 
 }
 
 void menuInput()
 {
-
     char choiceInput[20];
-
     char* choiceInputPointer;
-
     int selection;
     
-    int c;
-    scanf("%s",choiceInput);
+    scanf("%s", choiceInput);
+     int c;
     /*this loop flushes the input buffer for the upcoming getchar*/
     while ((c = getchar()) != '\n' && c != EOF) {};
+    selection = strtol(choiceInput, &choiceInputPointer, 10);
     
-    while(true)
+    while (!checkIfInteger(choiceInput) || !chooseOption(selection)) 
     {
-        selection = strtol(choiceInput,&choiceInputPointer,10);
-
-        if(chooseOption(selection) == true && checkIfInteger(choiceInput) == true)
-	{
-            switch(selection)
-	    {
-
-                case 1 : printf("\nLoginAsCostumer() function will be implemented here soon\n\n");
-
-                         break;
-
-                case 2 : collectCustomerProperties();
-                         break;
-
-                case 3 : printf("\nLoginAsEmployee() function will be implemented here soon\n\n");
+        printf("Input invalid! try again!\n");
 
-                         break;
+        scanf("%s", choiceInput);
+        while ((c = getchar()) != '\n' && c != EOF) {};
 
-                case 4 : printf("\e[1;1H\e[2J");
-
-			             printf("\nsee you next time !\n\n");
-
-                         break;
-                
-             }
-	    break;
-        }
+        selection = strtol(choiceInput, &choiceInputPointer, 10);
+    }
+    
+    switch(selection) 
+    {
+        case 1 : printf("\nLoginAsCostumer() function will be implemented here soon\n\n");
+                 break;
 
-        else
-        {
-            printf("Input invalid! try again!\n");
+        case 2 : collectCustomerProperties();
+                 break;
 
-	    scanf("%s",choiceInput);
-        }
-    }
+        case 3 : printf("\nLoginAsEmployee() function will be implemented here soon\n\n"); 
+                 break;
 
+        case 4 : printf("\e[1;1H\e[2J"); 
+                 printf("\nsee you next time !\n\n"); 
+                 break;
+    }     	
 }
 
+
 void showMenu()
 {