diff --git a/src/arithmeticAddition.c b/src/arithmeticAddition.c
index 8f93738..173c438 100644
--- a/src/arithmeticAddition.c
+++ b/src/arithmeticAddition.c
@@ -12,20 +12,20 @@ int* addition_integer(int num1, int num2) {
     return result;
 }
 
-double* addition_double(double number1, double number2) {
+double* addition_double(double num1, double num2) {
     double* result = malloc(sizeof(double));
-    *result = number1+number2;
+    *result = num1+num2;
     return result;
 }
 
-float* addition_float(float number1, float number2) {
+float* addition_float(float num1, float num2) {
     float* result = malloc(sizeof(float));
-    *result = number1+number2;
+    *result = num1+num2;
     return result;
 }
 
-long* addition_long(long number1, long number2) {
+long* addition_long(long num1, long num2) {
     long* result = malloc(sizeof(long));
-    *result = number1+number2;
+    *result = num1+num2;
     return result;
 }
\ No newline at end of file
diff --git a/src/arithmeticDivision.c b/src/arithmeticDivision.c
index 7cdfc7e..c29e7dd 100644
--- a/src/arithmeticDivision.c
+++ b/src/arithmeticDivision.c
@@ -4,6 +4,7 @@
 #include <stdlib.h>
 
 int* division_integer(int dividend, int divisor) {
+    // division with 0 would cause errors
     if(divisor == 0) {
         return NULL;
     }
@@ -14,4 +15,34 @@ int* division_integer(int dividend, int divisor) {
     int* result = malloc(sizeof(int));
     *result = dividend / divisor;
     return result;
+}
+
+long* division_long(long dividend, long divisor) {
+    // division with 0 would cause errors
+    if(divisor == 0) {
+        return NULL;
+    }
+    long* result = malloc(sizeof(long));
+    *result = dividend / divisor;
+    return result;
+}
+
+double* division_double(double dividend, double divisor) {
+    // division with 0 would cause errors
+    if(divisor == 0) {
+        return NULL;
+    }
+    double* result = malloc(sizeof(double ));
+    *result = dividend / divisor;
+    return result;
+}
+
+float* division_float(float dividend, float divisor) {
+    // division with 0 would cause errors
+    if(divisor == 0) {
+        return NULL;
+    }
+    float* result = malloc(sizeof(float));
+    *result = dividend / divisor;
+    return result;
 }
\ No newline at end of file
diff --git a/src/arithmeticDivision.h b/src/arithmeticDivision.h
index e4080b7..9ae1a34 100644
--- a/src/arithmeticDivision.h
+++ b/src/arithmeticDivision.h
@@ -3,4 +3,10 @@
 
 int* division_integer(int, int);
 
+long* division_long(long, long);
+
+double* division_double(double, double);
+
+float* division_float(float, float);
+
 #endif //THEADMIRALS_ARITHMETICDIVISION_H
diff --git a/src/arithmeticMultiplication_Double.c b/src/arithmeticMultiplication_Double.c
index 3207551..c33d245 100644
--- a/src/arithmeticMultiplication_Double.c
+++ b/src/arithmeticMultiplication_Double.c
@@ -5,7 +5,7 @@
 double* multiplication_double(double a, double b) {
     double* result = (double*)malloc(sizeof(double));
     if (result == NULL) {
-        return NULL; // Handle memory allocation failure
+        return NULL;
     }
     *result = a * b; // we multiply a times b and the result gets saved in *result
     return result;
diff --git a/src/arithmeticMultiplication_Float.c b/src/arithmeticMultiplication_Float.c
index 8e063f2..547b9d7 100644
--- a/src/arithmeticMultiplication_Float.c
+++ b/src/arithmeticMultiplication_Float.c
@@ -4,7 +4,7 @@
 float* multiplication_float(float a, float b) {
     float* result = (float*)malloc(sizeof(float));
     if (result == NULL) {
-        return NULL; // Handle memory allocation failure
+        return NULL;
     }
     *result = a * b;
     return result;
diff --git a/src/arithmeticMultiplication_Int.c b/src/arithmeticMultiplication_Int.c
index 1ad1a19..a00b05d 100644
--- a/src/arithmeticMultiplication_Int.c
+++ b/src/arithmeticMultiplication_Int.c
@@ -1,15 +1,11 @@
-
-
 #include "arithmeticMultiplication_Int.h"
 #include <stdlib.h>
 
 int* multiplication_integer(int a, int b) {
     int *result = (int*)malloc(sizeof(int));
     if (result == NULL) {
-        // Handle memory allocation failure
         return NULL;
     }
-
     *result = a * b;
 
     return result;
diff --git a/src/arithmeticSubtraction.c b/src/arithmeticSubtraction.c
index ed08d04..bbabad9 100644
--- a/src/arithmeticSubtraction.c
+++ b/src/arithmeticSubtraction.c
@@ -1,20 +1,22 @@
-
 #include "arithmeticSubtraction.h"
 
 #include <stdlib.h>
-//arithmetic Subtraction specification integer
+
+// arithmetic subtraction integer
 int* subtraction_integer(int a, int b) {
     int* result= malloc(sizeof (int));
     *result=a - b;
     return result;
 }
-//arithmetic Subtraction specification float
+
+// arithmetic subtraction float
 float* subtraction_float(float a, float b) {
     float* result= malloc(sizeof (float));
     *result=a - b;
     return result;
 }
-//arithmetic Subtraction specification double
+
+// arithmetic subtraction double
 double* subtraction_double(double a, double b) {
     double* result= malloc(sizeof (double));
     *result=a - b;
diff --git a/src/calculateFactorial.c b/src/calculateFactorial.c
index 0c6cbf0..bd7ae94 100644
--- a/src/calculateFactorial.c
+++ b/src/calculateFactorial.c
@@ -1,8 +1,8 @@
 
 
 #include "calculateFactorial.h"
-//Factorial
-// Function for Factorial
+
+// Function for Factorial with integer
 int calculateFactorial_integer(int n) {
     if (n < 0) {
 
@@ -17,4 +17,7 @@ int calculateFactorial_integer(int n) {
         }
         return result;
     }
+    return 0;
+
 }
+
diff --git a/src/convert_CM_in_M.c b/src/convert_CM_in_M.c
index bdc42ea..825caca 100644
--- a/src/convert_CM_in_M.c
+++ b/src/convert_CM_in_M.c
@@ -1,7 +1,7 @@
 
 #include "convert_CM_in_M.h"
 #include <stdio.h>
-//convert length
+//convert length for float cm into meter
 float cm_to_meter(float cm) {
     return cm / 100.0;
 }
diff --git a/src/convert_M_in_KM.c b/src/convert_M_in_KM.c
index 966872e..bf56016 100644
--- a/src/convert_M_in_KM.c
+++ b/src/convert_M_in_KM.c
@@ -1,7 +1,6 @@
-
 #include "convert_M_in_KM.h"
-#include <stdio.h>
-//convert length
+
+// convert length for double metre into kilometre
 double meter_to_kilometer(double meter) {
     return meter / 1000.0;
 }
diff --git a/src/convert_cm_in_dm.c b/src/convert_cm_in_dm.c
new file mode 100644
index 0000000..05d87e3
--- /dev/null
+++ b/src/convert_cm_in_dm.c
@@ -0,0 +1,7 @@
+
+#include "convert_cm_in_dm.h"
+#include <stdio.h>
+//convert length for double cm into dm
+double cm_to_dm(double cm) {
+    return cm / 10.0;
+}
diff --git a/src/convert_cm_in_dm.h b/src/convert_cm_in_dm.h
new file mode 100644
index 0000000..eafecd9
--- /dev/null
+++ b/src/convert_cm_in_dm.h
@@ -0,0 +1,7 @@
+
+#ifndef THEADMIRALS_CONVERT_CM_TO_DM_H
+#define THEADMIRALS_CONVERT_CM_TO_DM_H
+
+double cm_to_dm(double cm);
+
+#endif //THEADMIRALS_CONVERT_CM_TO_DM_H
diff --git a/src/convert_g_to_mg.c b/src/convert_g_to_mg.c
new file mode 100644
index 0000000..ceba263
--- /dev/null
+++ b/src/convert_g_to_mg.c
@@ -0,0 +1,6 @@
+
+#include "convert_g_to_mg.h"
+
+double g_to_mg(double grams) {
+    return grams * 1000.0;
+}
diff --git a/src/convert_g_to_mg.h b/src/convert_g_to_mg.h
new file mode 100644
index 0000000..e764c7e
--- /dev/null
+++ b/src/convert_g_to_mg.h
@@ -0,0 +1,17 @@
+
+#ifndef THEADMIRALS_CONVERT_G_TO_MG_H
+#define THEADMIRALS_CONVERT_G_TO_MG_H
+
+
+
+// Convert grams to milligrams
+// Parameters:
+//   grams: weight in grams
+// Returns:
+//   The equivalent weight in milligrams
+
+double g_to_mg(double grams);
+
+
+
+#endif //THEADMIRALS_CONVERT_G_TO_MG_H
diff --git a/src/convert_kg_to_g.c b/src/convert_kg_to_g.c
new file mode 100644
index 0000000..2ce2914
--- /dev/null
+++ b/src/convert_kg_to_g.c
@@ -0,0 +1,6 @@
+
+#include "convert_kg_to_g.h"
+
+double kg_to_gram(double kilograms) {
+    return kilograms * 1000.0;
+}
diff --git a/src/convert_kg_to_g.h b/src/convert_kg_to_g.h
new file mode 100644
index 0000000..15745dd
--- /dev/null
+++ b/src/convert_kg_to_g.h
@@ -0,0 +1,18 @@
+
+
+#ifndef THEADMIRALS_CONVERT_KG_TO_G_H
+#define THEADMIRALS_CONVERT_KG_TO_G_H
+
+
+
+// Convert kilograms to grams
+// Parameters:
+//   kilograms: weight in kilograms
+// Returns:
+//   The equivalent weight in grams
+
+double kg_to_gram(double kilograms);
+
+
+
+#endif //THEADMIRALS_CONVERT_KG_TO_G_H
diff --git a/src/convert_kg_to_ton.c b/src/convert_kg_to_ton.c
index 51cea7a..3803dce 100644
--- a/src/convert_kg_to_ton.c
+++ b/src/convert_kg_to_ton.c
@@ -2,5 +2,5 @@
 #include "convert_kg_to_ton.h"
 
 double kg_to_tons(double kilograms) {
-    return kilograms / 1000.0; // 1 ton = 1000 kilograms
+    return kilograms / 1000.0;
 }
diff --git a/src/convert_kg_to_ton.h b/src/convert_kg_to_ton.h
index 01f9369..cc38ea6 100644
--- a/src/convert_kg_to_ton.h
+++ b/src/convert_kg_to_ton.h
@@ -5,6 +5,12 @@
 
 
 
+// Convert kilograms to tons
+// Parameters:
+//   kilograms: weight in kilograms
+// Returns:
+//   The equivalent weight in tons
+
 double kg_to_tons(double kilograms);
 
 
diff --git a/src/convert_m_to_ft.c b/src/convert_m_to_ft.c
index 021c6b3..e488352 100644
--- a/src/convert_m_to_ft.c
+++ b/src/convert_m_to_ft.c
@@ -12,7 +12,7 @@ float convert_length(float value, char from_unit, char to_unit) {
     } else if (from_unit == 'i' && to_unit == 'c') {
         result = value * 2.54; // Inches to centimeters
     } else if (from_unit == 'c' && to_unit == 'i') {
-        result = value / 2.54; // Centimeters to inches
+        result = value / 2.54;
     } else {
         printf("Invalid units or conversion not supported.\n");
         result = -1; // Error code
@@ -20,4 +20,4 @@ float convert_length(float value, char from_unit, char to_unit) {
 
     return result;
 }
-
+// function converts between cm to inches and vice versa, and between m to ft and vice versa
diff --git a/src/convert_m_to_ft.h b/src/convert_m_to_ft.h
index 6b9317c..3c99725 100644
--- a/src/convert_m_to_ft.h
+++ b/src/convert_m_to_ft.h
@@ -2,6 +2,13 @@
 #ifndef THEADMIRALS_CONVERT_M_TO_FT_H
 #define THEADMIRALS_CONVERT_M_TO_FT_H
 
+// Convert length from one unit to another
+// Parameters:
+//   value: the value to be converted
+//   from_unit: the unit to convert from ('m' for meters, 'c' for centimeters, 'i' for inches)
+//   to_unit: the unit to convert to ('m' for meters, 'c' for centimeters, 'i' for inches)
+// Returns:
+//   The converted length value
 
 float convert_length(float value, char from_unit, char to_unit);
 
diff --git a/src/convert_time.c b/src/convert_time.c
index 86d93ca..2114697 100644
--- a/src/convert_time.c
+++ b/src/convert_time.c
@@ -36,11 +36,13 @@ double converter_sec_in_hour(double sec){
     return time;
 }
 
+// Converts Days in Years
 double converter_days_to_years(double days){
     double time = days / 365;
     return time;
 }
 
+// convert Years in days
 double converter_years_to_days(double years){
     double amount = years * 365;
     return amount;
diff --git a/src/convert_ton_to_kg.c b/src/convert_ton_to_kg.c
index 44202e2..d1653d8 100644
--- a/src/convert_ton_to_kg.c
+++ b/src/convert_ton_to_kg.c
@@ -3,5 +3,5 @@
 
 
 double tons_to_kg(double tons) {
-    return tons * 1000.0; // 1 ton = 1000 kilograms
+    return tons * 1000.0;
 }
diff --git a/src/convert_ton_to_kg.h b/src/convert_ton_to_kg.h
index 3ad55e5..9591ea6 100644
--- a/src/convert_ton_to_kg.h
+++ b/src/convert_ton_to_kg.h
@@ -3,6 +3,12 @@
 #ifndef THEADMIRALS_CONVERT_TON_TO_KG_H
 #define THEADMIRALS_CONVERT_TON_TO_KG_H
 
+// Convert tons to kilograms
+// Parameters:
+//   tons: weight in tons
+// Returns:
+//   The equivalent weight in kilograms
+
 
 double tons_to_kg(double tons);
 
diff --git a/src/convert_ton_to_mt.c b/src/convert_ton_to_mt.c
new file mode 100644
index 0000000..574d21e
--- /dev/null
+++ b/src/convert_ton_to_mt.c
@@ -0,0 +1,7 @@
+
+#include "convert_ton_to_mt.h"
+
+
+double tons_to_megatons(double tons) {
+    return tons / 1000000.0;
+}
diff --git a/src/convert_ton_to_mt.h b/src/convert_ton_to_mt.h
new file mode 100644
index 0000000..331c20b
--- /dev/null
+++ b/src/convert_ton_to_mt.h
@@ -0,0 +1,13 @@
+
+#ifndef THEADMIRALS_CONVERT_TON_TO_MT_H
+#define THEADMIRALS_CONVERT_TON_TO_MT_H
+
+
+
+
+double tons_to_megatons(double tons);
+
+
+
+
+#endif //THEADMIRALS_CONVERT_TON_TO_MT_H
diff --git a/src/inputHandler.c b/src/inputHandler.c
new file mode 100644
index 0000000..199d2dd
--- /dev/null
+++ b/src/inputHandler.c
@@ -0,0 +1,58 @@
+#include "inputHandler.h"
+#include <stdio.h>
+
+// return operation id for a specific symbol
+int getOperationIdBySymbol(char symbol) {
+    int id = 0;
+    switch (symbol) {
+        case '+':
+            return 1;
+        case '-':
+            return 2;
+        case '/':
+            return 3;
+        case '*':
+            return 4;
+        case '^':
+            return 5;
+        case '%':
+            return 6;
+        case '!':
+            return 7;
+    }
+    return id;
+}
+
+// returns operation symbol for a specific operation id
+char getOperationSymbolById(int id) {
+    char symbol = ' ';
+    switch (id) {
+        case 1:
+            return '+';
+        case 2:
+            return '-';
+        case 3:
+            return '/';
+        case 4:
+            return '*';
+        case 5:
+            return '^';
+        case 6:
+            return '%';
+        case 7:
+            return '!';
+    }
+    return symbol;
+}
+
+// Checking if operation id is available
+int isOperationIdValid(int id) {
+    if(id < 1 || id > 7) return 0;
+    return 1;
+}
+
+int isNumberTooBig(int number) {
+    if(number < 200) return 0;
+    //printf("This number is too big. Please choose a smaller one...\n");
+    return 1;
+}
\ No newline at end of file
diff --git a/src/inputHandler.h b/src/inputHandler.h
new file mode 100644
index 0000000..372f9d0
--- /dev/null
+++ b/src/inputHandler.h
@@ -0,0 +1,12 @@
+#ifndef THEADMIRALS_INPUTHANDLER_H
+#define THEADMIRALS_INPUTHANDLER_H
+
+int getOperationIdBySymbol(char);
+
+char getOperationSymbolById(int);
+
+int isOperationIdValid(int);
+
+int isNumberTooBig(int);
+
+#endif //THEADMIRALS_INPUTHANDLER_H
diff --git a/src/main.c b/src/main.c
index befd311..56241ed 100644
--- a/src/main.c
+++ b/src/main.c
@@ -6,14 +6,20 @@ char buffer[100];
 
 int main() {
     printf("Please enter the id of a specific operation...\n1. addition\n2. subtraction\n3. multiplication\n4. division\n");
+
+    // input for math operation as integer
     int input;
     scanf("%d", &input);
+
+    // check if operation input is valid
     if(!checkOperationInput(input)) {
         printf("Invalid operation id\n");
         return 0;
     }
+
     printf("\nPlease enter the first and the second number separated by a space...\n");
 
+    // loop to enter numbers for calculation
     while(fgets(buffer, 100, stdin)) {
         buffer[strcspn(buffer, "\n")] = '\0';
         if (strlen(buffer) > 0) {
@@ -21,7 +27,9 @@ int main() {
         }
     }
 
+    // extracting numbers from input
     int* result = evaluateInput(buffer, input);
+
     if(result == NULL) {
         printf("\nInvalid formatting. Two numbers need to be separated by a space\n");
         return 0;
diff --git a/src/operationHandler.c b/src/operationHandler.c
index 6fb44b8..df85a49 100644
--- a/src/operationHandler.c
+++ b/src/operationHandler.c
@@ -3,6 +3,7 @@
 #include <ctype.h>
 #include <stdlib.h>
 #include <string.h>
+#include <stdio.h>
 
 // checking integer input as operation id
 bool checkOperationInput(int input) {
@@ -94,4 +95,28 @@ int extractFirstNumber(char* str) {
     strcpy(str, temp);
 
     return number;
+}
+
+void outputInteger(int output) {
+    outputTemplate();
+    printf("Result: %d", output);
+}
+
+void outputLong(long output) {
+    outputTemplate();
+    printf("Result: %ld", output);
+}
+
+void outputDouble(double output) {
+    outputTemplate();
+    printf("Result: %lf", output);
+}
+
+void outputFloat(float output) {
+    outputTemplate();
+    printf("Result: %f", output);
+}
+
+void outputTemplate() {
+    printf("###############################\n-> Calculator\n#################################");
 }
\ No newline at end of file
diff --git a/src/operationHandler.h b/src/operationHandler.h
index 58ca89a..ad14eb2 100644
--- a/src/operationHandler.h
+++ b/src/operationHandler.h
@@ -10,4 +10,14 @@ bool containsTwoNumbers(const char*);
 
 int extractFirstNumber(char*);
 
+void outputInteger(int);
+
+void outputDouble(double);
+
+void outputFloat(float);
+
+void outputLong(long);
+
+void outputTemplate();
+
 #endif //THEADMIRALS_OPERATIONHANDLER_H
diff --git a/src/trigonometricFunctions.c b/src/trigonometricFunctions.c
index 0a9a956..6dbdfaf 100644
--- a/src/trigonometricFunctions.c
+++ b/src/trigonometricFunctions.c
@@ -3,20 +3,21 @@
 #include "math.h"
 #include <stdio.h>
 #include <stdlib.h>
-
+//function for trigonometric
+//Function 1 double
 double* calculate_sin_double(double angle) {
     double* result= malloc(sizeof (double));
     *result=sin(angle);
     return result;
 }
-
+//Function 2 double
 
 double* calculate_cos_double(double angle) {
     double* result= malloc(sizeof (double));
     *result=cos(angle);
     return result;
 }
-
+//Function 3 double
 
 double* calculate_tan_double(double angle) {
     double* result= malloc(sizeof (double));
diff --git a/team.md b/team.md
index 317f693..bb39ebd 100644
--- a/team.md
+++ b/team.md
@@ -1,4 +1,5 @@
 - Eric Bagus, fdai7812
+- fdai7812, fdai7812
 - Leon Wolf, fdai7845
 - Sandro Welte, fdai7728
 - Jonas Zitzmann, fdai7791
\ No newline at end of file
diff --git a/test/test_operationHandler.c b/test/test_operationHandler.c
index 1cdfb1d..cadef23 100644
--- a/test/test_operationHandler.c
+++ b/test/test_operationHandler.c
@@ -46,4 +46,11 @@ void test_operationHandler_extractingFirstNumber(void) {
     char str[] = {'4', '8', ' ', '5', '\0'};
     int result = extractFirstNumber(str);
     TEST_ASSERT_EQUAL_INT(expectedResult, result);
-}
\ No newline at end of file
+}
+
+void test_operationHandler_removefirstnumberfromoriginalstring(void) {
+    char expected[] = {'5', '\0'};
+    char str[] = {'4', '8', ' ', '5', '\0'};
+    extractFirstNumber(str);
+    TEST_ASSERT_EQUAL_STRING(expected, str);
+}