diff --git a/seminar04_templates/01_sum_even/main.cpp b/seminar04_templates/01_sum_even/main.cpp
new file mode 100644
index 0000000..badaefd
--- /dev/null
+++ b/seminar04_templates/01_sum_even/main.cpp
@@ -0,0 +1,18 @@
+#include <iostream>
+#include <vector>
+
+using std::cout, std::endl;
+
+int sumEven(const std::vector<int>& v) {
+    int sum = 0;
+    size_t s = v.size();
+    for (int i = 0; i < s; ++i)
+            if (v[i] % 2 == 0)
+                    sum += v[i];
+    return sum;
+}
+
+int main() {
+    std::vector<int> v {4, 8, 15, 16, 23, 42};
+    cout << sumEven(v) << endl;
+}
diff --git a/seminar04_templates/02_last_digits/main.cpp b/seminar04_templates/02_last_digits/main.cpp
new file mode 100644
index 0000000..87cd622
--- /dev/null
+++ b/seminar04_templates/02_last_digits/main.cpp
@@ -0,0 +1,58 @@
+#include <iostream>
+#include <vector>
+#include <span>
+
+using std::cout, std::endl, std::vector, std::span;
+
+vector<int> lastDigits1(const vector<int>& v) {
+    vector<int> result;
+    size_t size = v.size();
+    for(int i = 0; i < size; ++i) {
+        result.push_back(v[i] % 10);
+    }
+    return result;
+}
+void lastDigits2(vector<int>& v) {
+    size_t size = v.size();
+    for(int i = 0; i < size; ++i) {
+        v[i] %= 10;
+    }
+}
+
+void lastDigits3(vector<int>* pv) {
+    size_t size = pv->size();
+    for(int i = 0; i < size; ++i)
+            (*pv)[i] %= 10;
+}
+
+void lastDigits4(span<int> sp) {
+    size_t size = sp.size();
+    for(int i = 0; i < size; ++i)
+            sp[i] %= 10;
+}
+
+std::ostream& operator<<(std::ostream& out, const vector<int>& v) {
+    cout << "[";
+    size_t size = v.size();
+    for(int i = 0; i < size; ++i)
+        cout << v[i] << (i == size - 1 ? "]" : " ");
+    return out;
+}
+
+int main() {
+    vector<int> meow{1, 2, 3, 12, 45, 32,313123,3245};
+    vector<int> result1 = lastDigits1(meow);
+    cout << result1 << endl;
+
+    vector<int> result2 = meow;
+    lastDigits2(result2);
+    cout << result2 << endl;
+
+    vector<int> result3 = meow;
+    lastDigits3(&result3);
+    cout << result3 << endl;
+
+    span<int> sp = meow;
+    lastDigits4(sp);
+    cout << meow << endl;
+}
diff --git a/seminar04_templates/03_factorization/main.cpp b/seminar04_templates/03_factorization/main.cpp
new file mode 100644
index 0000000..fde4487
--- /dev/null
+++ b/seminar04_templates/03_factorization/main.cpp
@@ -0,0 +1,74 @@
+#include <iostream>
+#include <utility>
+#include <vector>
+#include <cmath>
+
+using std::cout, std::endl, std::pair, std::vector;
+
+int next_prime(int n);
+
+vector<pair<int, int>> factorization(int n) {
+    if (n == 1) {
+        return vector<pair<int,int>>{{1, 1}};
+    }
+    int d = 2;
+    int c;
+    vector<pair<int, int>> result;
+    
+    while(n != 1) {
+        c = 0;
+        while(n % d == 0) {
+            c++;
+            n /= d;
+        }
+        if (c)
+            result.push_back(pair{d, c});
+        d = next_prime(d);
+    }
+    return result;
+}
+
+bool is_prime(int n) {
+    bool prime = true;
+    for(int i = 2; i <= static_cast<int>(std::sqrt(n)); i++) {
+        if (n % i == 0) {
+            prime = false;
+            break;
+        }
+    }
+    return prime;
+}
+
+int next_prime(int n) {
+    ++n;
+    while (true) {
+        if (is_prime(n))
+                return n;
+        ++n;
+    }
+}
+
+std::ostream& operator<<(std::ostream& out, pair<int,int> p) {
+    out << "{" << p.first << ", " << p.second << "}";
+    return out;
+}
+
+std::ostream& operator<<(std::ostream& out, vector<pair<int,int>> v) {
+    out << "{";
+    size_t size = v.size();
+    for(int i = 0; i < size; ++i) {
+        out << v[i] << (i == size - 1 ? "}" : ", ");
+    }
+    return out;
+}
+
+int main() {
+        vector<pair<int, int>> res = factorization(60);
+        cout << res << endl;
+        res = factorization(626215995);
+        cout << res << endl;
+        res = factorization(107);
+        cout << res << endl;
+        res = factorization(1);
+        cout << res << endl;
+}
diff --git a/seminar04_templates/04_time/main.cpp b/seminar04_templates/04_time/main.cpp
new file mode 100644
index 0000000..6f99c57
--- /dev/null
+++ b/seminar04_templates/04_time/main.cpp
@@ -0,0 +1,27 @@
+#include <iostream>
+#include "time.h"
+#include <string_view>
+#include <string>
+#include <vector>
+
+using std::cout, std::endl, std::string, std::string_view, std::vector;
+
+int main()
+{
+    string t1s = "23:59:59";
+    string_view t1sv = t1s;
+    string t2s = "23:59:59";
+    string_view t2sv = t2s;
+
+    Time t1 = t1sv;
+    Time t2 = t2sv;
+    cout << t1 + t2 << endl;
+
+    string tss = "23:59:59 23:59:59 23:59:59";
+    string_view tssv = tss;
+    vector < Time > tsv = getTimesFromString(tss);
+    for (int i = 0, size = tsv.size(); i < size; ++i) {
+	cout << tsv[i] << endl;
+    }
+    cout << sumTimes(tsv) << endl;
+}
diff --git a/seminar04_templates/04_time/time.cpp b/seminar04_templates/04_time/time.cpp
new file mode 100644
index 0000000..afc7c1d
--- /dev/null
+++ b/seminar04_templates/04_time/time.cpp
@@ -0,0 +1,81 @@
+#include "time.h"
+#include <string>
+#include <iomanip>
+#include <vector>
+
+using std::cout, std::endl, std::vector, std::string_view, std::string;
+
+Time::Time(int hours, int minutes, int seconds)
+{
+    mHours = hours;
+    mMinutes = minutes;
+    mSeconds = seconds;
+}
+
+Time::Time(string_view s)
+{
+    string buf;
+    buf[0] = s[0];
+    buf[1] = s[1];
+    mHours = stoi(buf);
+    buf[0] = s[3];
+    buf[1] = s[4];
+    mMinutes = stoi(buf);
+    buf[0] = s[6];
+    buf[1] = s[7];
+    mSeconds = stoi(buf);
+}
+
+Time::Time():Time(0, 0, 0)
+{
+};
+
+Time Time::operator+(Time b) const
+{
+    return Time((mHours + b.mHours + (mMinutes + b.mMinutes) / 60) % 24,
+		(mMinutes + b.mMinutes +
+		 (mSeconds + b.mSeconds) / 60) % 60,
+		(mSeconds + b.mSeconds) % 60);
+}
+
+int Time::hours() const
+{
+    return mHours;
+}
+
+int Time::minutes() const
+{
+    return mMinutes;
+}
+
+int Time::seconds() const
+{
+    return mSeconds;
+}
+
+vector < Time > getTimesFromString(string_view s)
+{
+    vector < Time > res;
+    for (int i = 0, size = s.size(); i < size; i += 9) {
+	res.push_back(Time(s.substr(i, 9)));
+    }
+    return res;
+}
+
+Time sumTimes(vector < Time > &v)
+{
+    Time res;
+    for (int i = 0, size = v.size(); i < size; ++i) {
+	res = res + v[i];
+    }
+    return res;
+}
+
+std::ostream & operator<<(std::ostream & out, Time t)
+{
+    out << std::setw(2) << std::setfill('0') << t.mHours
+	<< ":"
+	<< std::setw(2) << std::setfill('0') << t.mMinutes
+	<< ":" << std::setw(2) << std::setfill('0') << t.mSeconds;
+    return out;
+}
diff --git a/seminar04_templates/04_time/time.h b/seminar04_templates/04_time/time.h
new file mode 100644
index 0000000..68a4d92
--- /dev/null
+++ b/seminar04_templates/04_time/time.h
@@ -0,0 +1,21 @@
+#pragma once
+#include <string_view>
+#include <iostream>
+#include <vector>
+
+using std::string_view, std::vector;
+
+class Time {
+private:
+        int mHours = 0, mMinutes = 0, mSeconds = 0;
+public:
+        Time(int hours, int minutes, int seconds);
+        Time();
+        Time(string_view s);
+        Time operator+(Time b) const;
+        int hours() const; int minutes() const; int seconds() const;
+        friend std::ostream& operator<<(std::ostream& out, Time t);
+};
+
+Time sumTimes(vector<Time>& v);
+vector<Time> getTimesFromString(string_view s);
diff --git a/seminar04_templates/homework_templates.pdf b/seminar04_templates/homework_templates.pdf
new file mode 100644
index 0000000..7c1c62d
Binary files /dev/null and b/seminar04_templates/homework_templates.pdf differ
diff --git a/seminar04_templates/pairing_test.cpp b/seminar04_templates/pairing_test.cpp
new file mode 100644
index 0000000..a7e2f93
--- /dev/null
+++ b/seminar04_templates/pairing_test.cpp
@@ -0,0 +1,55 @@
+#include <iostream>
+#include <vector>
+#include <array>
+#include <string>
+#include <utility>
+using std::cout, std::endl;
+
+template <typename T>
+std::ostream& operator<<(std::ostream& out, const std::vector<T>& v)
+{
+    out << "[";
+    for (size_t i = 0; i < v.size() - 1; ++i)
+        out << v[i] << ", ";
+
+    if (!v.empty())
+    {
+        out << v.back();
+    }
+    out << "]";
+    return out;
+}
+
+template <typename T, typename U>
+std::ostream& operator<<(std::ostream& out, const std::pair<T, U>& p)
+{
+    out << "(" << p.first << ", " << p.second << ")";
+    return out;
+}
+
+
+// Нужно написать функцию pairing
+
+
+int main()
+{
+    std::vector v {10, 20, 30, 40, 50, 60};
+    cout << pairing(v) << endl;
+
+
+    std::array<std::string, 7> a {"cat", "dog", "mouse", "elephant", "tiget", "axolotl", "wolf"};
+    cout << pairing(a) << endl;
+
+
+    std::string s {"Cats and dogs!"};
+    cout << pairing(s) << endl;
+}
+
+
+/*
+    Программа должна напечатать:
+
+    [(10, 20), (30, 40), (50, 60)]
+    [(cat, dog), (mouse, elephant), (tiget, axolotl), (wolf, )]
+    [(C, a), (t, s), ( , a), (n, d), ( , d), (o, g), (s, !)]
+*/
\ No newline at end of file