diff --git a/ex1/ABCEFG/skalar_stl/main.cpp b/ex1/ABCEFG/skalar_stl/main.cpp
index d2bd2b0..ba34d8b 100644
--- a/ex1/ABCEFG/skalar_stl/main.cpp
+++ b/ex1/ABCEFG/skalar_stl/main.cpp
@@ -13,7 +13,7 @@
 #include <stdexcept>
 using namespace std;
 
-void task_a() {
+static void task_a() {
     printf("\n\n-------------- Task A --------------\n\n");
 
     auto [a,b,c] = means0(1,4,16);
@@ -30,7 +30,7 @@ void task_a() {
 
 }
 
-void task_b() {
+static void task_b() {
     printf("\n\n-------------- Task B --------------\n\n");
     
     // Read vector
@@ -57,11 +57,11 @@ void task_b() {
     printf("Harmonic: %f\n", z);
 
     // deviation
-    double deviation;
+    double deviation(0.0);
     for (long unsigned int i=0; i<a.size(); i++){
         deviation += pow(x - a.at(i),2);
     }
-    deviation = sqrt(deviation/a.size());
+    deviation = sqrt(deviation/static_cast<double>(a.size()));
     printf("Deviation: %f\n", deviation);
 
     // write results to file
@@ -70,14 +70,14 @@ void task_b() {
 
 }
 
-void task_c() {
+static void task_c() {
     printf("\n\n-------------- Task C --------------\n\n");
 
     vector<int> n_values = {15, 1001, 1432987};
     
     for (int n : n_values) {
         printf("n = %d\n", n);
-        double sum = 0;
+        long int sum = 0;
         double loops = 1000;
 
         // Timing first function
@@ -86,24 +86,24 @@ void task_c() {
             sum = sum_of_spec(n);
         }
         double sec1 = toc();
-        printf("For-loop funtion: result = %.f | time = %f milliseconds\n", sum, sec1*1000);
+        printf("For-loop funtion: result = %ld | time = %f milliseconds\n", sum, sec1*1000);
         
         // Timing second function
         tic();
         for (int i=0; i<loops; i++){
-            sum = formula(n);
+            sum = static_cast<long int>(formula(n));
         }
         double sec2 = toc();
-        printf("Formula funtion:  result = %.f | time = %f milliseconds\n", sum, sec2*1000);
+        printf("Formula funtion:  result = %ld | time = %f milliseconds\n", sum, sec2*1000);
         }
 }
 
-void task_d() {
+static void task_d() {
     printf("\n\n-------------- Task D --------------\n\n");
     printf("See folder D.\n");
 }
 
-void task_e() {
+static void task_e() {
     printf("\n\n-------------- Task E --------------\n\n");
 
     for (int n : {100, 1000, 10000}) {
@@ -130,7 +130,7 @@ void task_e() {
     }
 }
 
-void task_f() {
+static void task_f() {
     printf("\n\n-------------- Task F --------------\n\n");
 
     // single_goldbach(k)
@@ -161,7 +161,7 @@ void task_f() {
 
 }
 
-void task_g() {
+static void task_g() {
     printf("\n\n-------------- Task G --------------\n\n");
 
     DenseMatrix const M(5,3);
@@ -188,7 +188,7 @@ void task_g() {
     // #######################################################
 
     int const NLOOPS = 100;
-    int const n = 1000;
+    int const n = 3000;
 
     // Time initialization
     tic();
@@ -200,7 +200,7 @@ void task_g() {
     // Time Mult
     tic();
     vector<double> f3 = M2.Mult(w);
-    for (int k=1; k<NLOOPS; ++k){
+    for (size_t k=1; k<NLOOPS; ++k){
         f3 = M2.Mult(w);
     }
     double t2 = toc();
@@ -208,8 +208,8 @@ void task_g() {
     // Time MultT
     tic();
     vector<double> f4 = M2.MultT(w);
-    for (int k=1; k<NLOOPS; ++k){
-        f4 = M2.Mult(w);
+    for (size_t k=1; k<NLOOPS; ++k){
+        f4 = M2.MultT(w);
     }
     double t3 = toc();
 
@@ -220,7 +220,7 @@ void task_g() {
     printf("Time for MultT         : %f seconds, %f per loop.\n", t3, t3/NLOOPS);
 
     // Check if resulting vectors are equal
-    for (int i = 0; i < n; i++)
+    for (size_t i = 0; i < n; i++)
     {
         double err = f3[i] - f4[i];
         if(abs(err) > 1e-4)
@@ -233,14 +233,14 @@ void task_g() {
     // Time initialization
     tic();
     vector<double> x(n,0);
-    for (int i=0; i<n; i++){x[i] = sigmoid( (10.0*i)/(n-1) - 5 );}
+    for (int i=0; i<n; i++){x[i] = sigmoid( (10.0*static_cast<double>(i))/(n-1) - 5 );}
     DenseMatrix2 M3(x,x);
     double t4 = toc();
 
     // Time Mult
     tic();
     vector<double> f5 = M3.Mult(w);
-    for (int k=1; k<NLOOPS; ++k){
+    for (size_t k=1; k<NLOOPS; ++k){
         f5 = M3.Mult(w);
     }
     double t5 = toc();
@@ -248,8 +248,8 @@ void task_g() {
     // Time MultT
     tic();
     vector<double> f6 = M3.MultT(w);
-    for (int k=1; k<NLOOPS; ++k){
-        f6 = M3.Mult(w);
+    for (size_t k=1; k<NLOOPS; ++k){
+        f6 = M3.MultT(w);
     }
     double t6 = toc();
     
@@ -260,7 +260,7 @@ void task_g() {
     printf("Time for MultT         : %f seconds, %f per loop.\n", t6, t6/NLOOPS);
 
     // Check if resulting vectors are equal
-    for (int i = 0; i < n; i++)
+    for (size_t i = 0; i < n; i++)
     {
         double err = f5[i] - f6[i];
         if(abs(err) > 1e-4)
@@ -269,9 +269,6 @@ void task_g() {
         }
     }
 
-    printf("\nNOTE: difference in runtime noticable with n=10.000 (~30 seconds)\n");
-
-
 }
 
 
@@ -286,4 +283,4 @@ int main(){
     task_g();
 
     return 0;
-};
\ No newline at end of file
+}
diff --git a/ex1/ABCEFG/skalar_stl/mylib.cpp b/ex1/ABCEFG/skalar_stl/mylib.cpp
index fbea237..9348cec 100644
--- a/ex1/ABCEFG/skalar_stl/mylib.cpp
+++ b/ex1/ABCEFG/skalar_stl/mylib.cpp
@@ -18,26 +18,26 @@ using namespace std;
 
 tuple<double, double, double> means0(double a, double b, double c){
     double arith = (a+b+c) / 3;
-    double geo = pow((a*b*c), 1.0f/3);
-    double harm = 3 / ((1.0f/a) + (1.0f/b) + (1.0f/c));
+    double geo = pow((a*b*c), 1.0/3);
+    double harm = 3 / ((1.0/a) + (1.0/b) + (1.0/c));
     return make_tuple(arith, geo, harm);
 }
 
 tuple<double, double, double> means(const vector<double>& v){
-    int n = v.size();
+    size_t n = v.size();
     double sum = 0;
-    double prod = 1;
+    double logsum = 0;
     double invsum = 0;
 
-    for (int i = 0; i<n; ++i){
+    for (size_t i = 0; i<n; ++i){
         sum += v[i];
-        prod *= v[i];
-        invsum += 1.0f/v[i];
+        logsum += log(v[i]);
+        invsum += 1.0/v[i];
     }
 
-    double arith = sum / n;
-    double geo = pow(prod, 1.0f/n);
-    double harm = n / invsum;
+    double arith = sum / static_cast<double>(n);
+    double geo = exp(1.0/static_cast<double>(n) * logsum);
+    double harm = static_cast<double>(n) / invsum;
     return make_tuple(arith, geo, harm);
 }
 
@@ -84,7 +84,7 @@ void write_vector_to_file(const string& file_name, const vector<double>& v)
     ofstream fout(file_name);          // Oeffne das File im ASCII-Modus
     if( fout.is_open() )
     {
-       for (unsigned int k=0; k<v.size(); ++k)
+       for (size_t k=0; k<v.size(); ++k)
        {
           fout << v.at(k) << endl;
        }
@@ -100,10 +100,10 @@ void write_vector_to_file(const string& file_name, const vector<double>& v)
 
 // -------------- Task C --------------
 
-double sum_of_spec(int n)
+long int sum_of_spec(int n)
 {
     long int sum = 0;
-    for (int i=1; i<n+1; i++){
+    for (long int i=1; i<n+1; i++){
         if (i % 3 == 0 ||  i % 5 == 0){
             sum += i;
         }
@@ -113,13 +113,13 @@ double sum_of_spec(int n)
 
 double formula(int n)
 {
-    double div_by_3 = floor( n / 3.0f );
-    double div_by_5 = floor( n / 5.0f );
-    double div_by_15 = floor( n / 15.0f );
+    double div_by_3 = floor( n / 3.0 );
+    double div_by_5 = floor( n / 5.0 );
+    double div_by_15 = floor( n / 15.0 );
 
-    double S_3 = 3.0 * (div_by_3*((div_by_3+1)/2.0f));
-    double S_5 = 5.0 * (div_by_5*((div_by_5+1)/2.0f));
-    double S_15 = 15.0 * (div_by_15*((div_by_15+1)/2.0f));
+    double S_3 = 3.0 * (div_by_3*((div_by_3+1)/2.0));
+    double S_5 = 5.0 * (div_by_5*((div_by_5+1)/2.0));
+    double S_15 = 15.0 * (div_by_15*((div_by_15+1)/2.0));
 
     double sum = S_3 + S_5 - S_15;
 
@@ -215,15 +215,15 @@ double DenseMatrix::sigmoid(double x)
     return 1.0 / (1.0 + exp(-x));
 }
 
-DenseMatrix::DenseMatrix(int n, int m) : rows(n), cols(m), matrix(n*m)
+DenseMatrix::DenseMatrix(size_t n, size_t m) : rows(n), cols(m), matrix(n*m)
 {
-    int nm = max(n, m);
+    size_t nm = max(n, m);
     for (size_t i = 0; i < rows; i++)
     {
         for (size_t j = 0; j < cols; j++)
         {
-            double x_i = 10.0*i/(nm-1) - 5.0;
-            double x_j = 10.0*j/(nm-1) - 5.0;
+            double x_i = 10.0*static_cast<double>(i)/(nm-1) - 5.0;
+            double x_j = 10.0*static_cast<double>(j)/(nm-1) - 5.0;
             matrix[i*cols + j] = sigmoid(x_i) * sigmoid(x_j);
         }
     }
@@ -260,7 +260,7 @@ vector<double> DenseMatrix::MultT(const vector<double>& vec) const
 }
 
 void DenseMatrix::print() const {
-    int count(0);
+    size_t count(0);
     cout.precision(5);
     for (double val : matrix) {
         printf("%.6f ", val);
@@ -308,4 +308,13 @@ vector<double> DenseMatrix2::MultT(const vector<double>& vec) const
     }
 
     return result;
-}
\ No newline at end of file
+}
+
+
+void task_a();
+void task_b();
+void task_c();
+void task_d();
+void task_e();
+void task_f();
+void task_g();
diff --git a/ex1/ABCEFG/skalar_stl/mylib.h b/ex1/ABCEFG/skalar_stl/mylib.h
index 554a1f5..7540de4 100644
--- a/ex1/ABCEFG/skalar_stl/mylib.h
+++ b/ex1/ABCEFG/skalar_stl/mylib.h
@@ -56,10 +56,10 @@ void fill_vector(istream& istr, vector<double>& v);
 // -------------- Task C --------------
 
 // Sums up all positive integers less or equal n which are multiples of 3 or of 5 (including or!) by brute force.
-double sum_of_spec(int n);
+long int sum_of_spec(int n);
 
 // Sums up all positive integers less or equal n which are multiples of 3 or of 5 (including or!) by inclusion-exclusion principle. 
-double formula(int n);
+double formula(long int n);
 
 // -------------- Task E --------------
 
@@ -93,7 +93,7 @@ private:
     size_t cols;
     vector<double> matrix;
 public:
-    DenseMatrix(int n, int m); // Constructor
+    DenseMatrix(size_t n, size_t m); // Constructor
     vector<double> Mult(const vector<double>& vec) const;
     vector<double> MultT(const vector<double>& vec) const;
     void print() const;
@@ -109,4 +109,4 @@ public:
     DenseMatrix2(vector<double> const u, vector<double> const v); // Constructor
     vector<double> Mult(const vector<double>& vec) const;
     vector<double> MultT(const vector<double>& vec) const;
-};
\ No newline at end of file
+};