diff --git a/lab9/t1.c b/lab9/t1.c
new file mode 100644
index 0000000..f0b3d00
--- /dev/null
+++ b/lab9/t1.c
@@ -0,0 +1,97 @@
+#define _CRT_SECURE_NO_WARNINGS
+#include <stdio.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <inttypes.h>
+#include <stdlib.h>
+#include <ctype.h>
+
+// Lab 10 Task 1
+
+typedef struct {
+    uint16_t year;
+    uint16_t month;
+    uint16_t day;
+} Date;
+
+typedef struct {
+    uint8_t r : 3;
+    uint8_t f : 3;
+} ChessSquare;
+
+typedef struct {
+    float x, y;
+} Point;
+
+typedef struct {
+    Point a, b;
+} AARect;
+
+typedef struct {
+    size_t n;
+    // array from n+1 element;
+    double* coefficients;
+} Poly;
+
+void input_date(Date* date) {
+    scanf("%" SCNu16 "%" SCNu16 "%" SCNu16, &date->day, &date->month, &date->year);
+}
+
+void print_date(const Date* date) {
+    printf("%" PRIu16 ".%" PRIu16 ".%" PRIu16, date->day, date->month, date->year);
+}
+
+bool input_square(ChessSquare* square) {
+    char f, r;
+    if (2 != scanf("%c%c", &f, &r))
+        return false;
+    f = (char)toupper(f);
+    if (f < 'A' || f > 'H' || r < '1' || r > '7')
+        return false;
+    square->f = f - 'A';
+    square->r = r - '1';
+    return true;
+}
+
+void print_square(const ChessSquare* square) {
+    printf("%c%c", (char)(square->f + 'A'), (char)(square->r + '1'));
+}
+
+void input_rect(AARect* rect) {
+    scanf("%f%f%f%f", &rect->a.x, &rect->a.y, &rect->b.x, &rect->b.y);
+}
+
+void print_rect(const AARect* rect) {
+    printf("(%f, %f) (%f, %f)", rect->a.x, rect->a.y, rect->b.x, rect->b.y);
+}
+
+void free_poly(Poly* poly) {
+    if (poly->coefficients) {
+        free(poly->coefficients);
+    }
+}
+
+void input_poly(Poly* poly) {
+    free_poly(poly);
+    size_t n;
+    scanf("%zu", &n);
+    poly->n = n;
+    poly->coefficients = (double*)malloc(sizeof(double) * (n+1));
+    for (size_t i = 0; i <= n; i++) scanf("%lf", poly->coefficients+i);
+}
+
+void print_poly(const Poly* poly) {
+    if (!poly || !poly->coefficients) return;
+    printf("%zu", poly->n);
+    for (size_t i = poly->n; i >= 1; i--)
+        printf("%lf * x^%zu + ", poly->coefficients[i], i);
+    printf("%lf", poly->coefficients[0]);
+}
+
+int main(void){
+    Poly poly = { 0 };
+    input_poly(&poly);
+    poly.coefficients[0] = 42;
+    print_poly(&poly);
+    free_poly(&poly);
+}
\ No newline at end of file
diff --git a/lab9/t14a.c b/lab9/t14a.c
new file mode 100644
index 0000000..9b6a91f
--- /dev/null
+++ b/lab9/t14a.c
@@ -0,0 +1,44 @@
+#include <stdio.h>
+
+struct Person {
+    int nameNumber;
+    char gender;
+    float height;
+};
+
+float averageHeightOfWomen(struct Person L[], struct Person P[], int sizeL, int sizeP) {
+    int womenCount = 0;
+    float totalHeight = 0;
+
+    for (int i = 0; i < sizeP; ++i) {
+        if (P[i].gender == 'F') {
+            for (int j = 0; j < sizeL; ++j) {
+                if (L[j].nameNumber == P[i].nameNumber) {
+                    totalHeight += L[j].height;
+                    womenCount++;
+                    break;
+                }
+            }
+        }
+    }
+
+    if (womenCount > 0) {
+        return totalHeight / womenCount;
+    } else {
+        return 0.0;
+    }
+}
+
+int main() {
+    struct Person L[] = {{1, 'M', 175.5}, {2, 'F', 160.0}, {3, 'M', 180.0}};
+    struct Person P[] = {{2, 'F', 165.5}, {1, 'M', 178.0}};
+
+    int sizeL = sizeof(L) / sizeof(L[0]);
+    int sizeP = sizeof(P) / sizeof(P[0]);
+
+    float averageWomenHeight = averageHeightOfWomen(L, P, sizeL, sizeP);
+
+    printf("AFH: %.2f\n", averageWomenHeight);
+
+    return 0;
+}
diff --git a/lab9/t14b.c b/lab9/t14b.c
new file mode 100644
index 0000000..46321c1
--- /dev/null
+++ b/lab9/t14b.c
@@ -0,0 +1,46 @@
+#include <stdio.h>
+
+struct Person {
+    int nameNumber;
+    char gender;
+    float height;
+};
+
+int findTallestMan(struct Person L[], struct Person P[], int sizeL, int sizeP) {
+    int tallestManIndex = -1;
+
+    float maxManHeight = 0;
+
+    for (int i = 0; i < sizeP; ++i) {
+        if (P[i].gender == 'M') {
+            for (int j = 0; j < sizeL; ++j) {
+                if (L[j].nameNumber == P[i].nameNumber) {
+                    if (P[i].height > maxManHeight) {
+                        maxManHeight = P[i].height;
+                        tallestManIndex = j;
+                    }
+                    break;
+                }
+            }
+        }
+    }
+
+    return tallestManIndex;
+}
+
+int main() {
+    struct Person L[] = {{1, 'M', 175.5}, {2, 'F', 160.0}, {3, 'M', 180.0}};
+    struct Person P[] = {{2, 'F', 165.5}, {1, 'M', 178.0}, {3, 'M', 185.0}};
+
+    int sizeL = sizeof(L) / sizeof(L[0]);
+    int sizeP = sizeof(P) / sizeof(P[0]);
+    int indexTallestMan = findTallestMan(L, P, sizeL, sizeP);
+
+    if (indexTallestMan != -1) {
+        printf("highest man name: %d\n", L[indexTallestMan].nameNumber);
+    } else {
+        printf("no high man.\n");
+    }
+
+    return 0;
+}
diff --git a/lab9/t2.c b/lab9/t2.c
new file mode 100644
index 0000000..6c8d1c8
--- /dev/null
+++ b/lab9/t2.c
@@ -0,0 +1,46 @@
+#define _CRT_SECURE_NO_WARNINGS
+#include <stdio.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <inttypes.h>
+#include <stdlib.h>
+#include <ctype.h>
+
+// Lab 10 Task 2
+
+typedef struct {
+    uint8_t r : 3;
+    uint8_t f : 3;
+} ChessSquare;
+
+bool input_square(ChessSquare* square) {
+    char f, r;
+    if (2 != scanf("%c%c", &f, &r))
+        return false;
+    f = (char)toupper(f);
+    if (f < 'A' || f > 'H' || r < '1' || r > '7')
+        return false;
+    square->f = f - 'A';
+    square->r = r - '1';
+    return true;
+}
+
+void print_square(const ChessSquare* square) {
+    printf("%c%c", (char)(square->f + 'A'), (char)(square->r + '1'));
+}
+
+bool can_queen_move(ChessSquare from, ChessSquare to) {
+    return from.r == to.r || from.f == to.f ||
+           from.r - from.f == to.r - to.f ||
+           from.r + from.f == to.r + to.f;
+}
+
+int main(void) {
+    ChessSquare a, b;
+    bool is_corect_input = input_square(&a) && input_square(&b);
+    if (!is_corect_input) {
+        printf("incorrect input\n");
+        return 0;
+    }
+    printf("%s", can_queen_move(a, b) ? "true" : "false");
+}
\ No newline at end of file
diff --git a/lab9/t3.c b/lab9/t3.c
new file mode 100644
index 0000000..eb35f04
--- /dev/null
+++ b/lab9/t3.c
@@ -0,0 +1,46 @@
+#define _CRT_SECURE_NO_WARNINGS
+#include <stdio.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+// Lab 10 Task 3
+
+typedef struct {
+    uint16_t year;
+    uint16_t month;
+    uint16_t day;
+} Date;
+
+bool is_leap_year(uint16_t y) {
+    return y % 4 == 0 && y % 100 != 0 || y % 400 == 0;
+}
+
+uint16_t days_in_month(uint16_t m, bool is_leap) {
+    const uint16_t d[12] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
+    return d[m] + (uint16_t)(is_leap && m == 1);
+}
+
+Date next_day(Date date) {
+    date.day += 1;
+    bool is_leap = is_leap_year(date.year);
+    uint16_t d = days_in_month(date.month, is_leap);
+    if (date.day < d) return date;
+    date.day -= d;
+    date.month += 1;
+    if (date.month < 12) return date;
+    date.month -= 12;
+    date.year += 1;
+    return date;
+}
+
+int main(void) {
+    // today date: 26.10.23
+    const Date today = (Date){
+            .day = 25,
+            .month = 9,
+            .year = 2022,
+    };
+
+    const Date tomorrow = next_day(today);
+    printf("%02hu.%02hu.%04hu", tomorrow.day+1, tomorrow.month+1, tomorrow.year+1);
+}
\ No newline at end of file
diff --git a/lab9/t4.c b/lab9/t4.c
new file mode 100644
index 0000000..3cc59fd
--- /dev/null
+++ b/lab9/t4.c
@@ -0,0 +1,69 @@
+#define _CRT_SECURE_NO_WARNINGS
+#include <stdio.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <math.h>
+
+// Lab 10 Task 4
+
+typedef struct {
+    int nomirator;
+    unsigned denomirator;
+} Rational;
+
+inline Rational rat_from_int(int num) {
+    return (Rational) { num, 1 };
+}
+
+inline void rat_display(Rational rat) {
+    printf("%d/%u", rat.nomirator, rat.denomirator);
+}
+
+inline unsigned gcd_impl(unsigned a, unsigned b) {
+    if (b == 0) return a;
+    return gcd_impl(b, a%b);
+}
+
+inline Rational rat_simplify(Rational rat) {
+    unsigned nom = (unsigned)abs(rat.nomirator);
+    unsigned common = gcd_impl(nom, rat.denomirator);
+    rat.nomirator /= common;
+    rat.denomirator /= common;
+    return rat;
+}
+
+inline Rational rat_add(Rational a, Rational b) {
+    b.nomirator *= a.denomirator;
+    a.nomirator *= b.denomirator;
+    a.denomirator *= b.denomirator;
+    a.nomirator += b.nomirator;
+    return rat_simplify(a);
+}
+
+inline Rational rat_sub(Rational a, Rational b) {
+    b.nomirator *= a.denomirator;
+    a.nomirator *= b.denomirator;
+    a.denomirator *= b.denomirator;
+    a.nomirator -= b.nomirator;
+    return rat_simplify(a);
+}
+
+inline Rational rat_mul(Rational a, Rational b) {
+    a.nomirator *= b.nomirator;
+    a.denomirator *= b.denomirator;
+    return rat_simplify(a);
+}
+
+inline Rational rat_div(Rational a, Rational b) {
+    a.denomirator *= b.nomirator;
+    a.nomirator *= b.denomirator;
+    return rat_simplify(a);
+}
+
+inline int rat_cmp(Rational a, Rational b) {
+    return a.nomirator * b.denomirator - b.nomirator * a.denomirator;
+}
+
+int main(void) {
+    // TODO
+}
\ No newline at end of file
diff --git a/lab9/t5.c b/lab9/t5.c
new file mode 100644
index 0000000..d74e10e
--- /dev/null
+++ b/lab9/t5.c
@@ -0,0 +1,73 @@
+#define _CRT_SECURE_NO_WARNINGS
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+// Lab 10 Task 5
+
+#define MAX_NAME_SIZE 32
+
+typedef struct {
+    const char* name;
+    double height;
+} MountainData;
+
+MountainData mntn_input() {
+    char* name = malloc(MAX_NAME_SIZE);
+    MountainData data = {
+            .name = name,
+    };
+    printf("name ?= ");
+    scanf("%s", name);
+    printf("height ?= ");
+    scanf("%lf", &data.height);
+    return data;
+}
+
+void mntn_display(const MountainData* data) {
+    printf("%s: %lf\n", data->name, data->height);
+}
+
+int mntn_find_heightest(const MountainData* data, int count) {
+    double h = -1.;
+    int index = -1;
+    for (int i = 0; i < count; i++) {
+        if (data[i].height > h) {
+            h = data[i].height;
+            index = i;
+        }
+    }
+    return index;
+}
+
+int mntn_find_by_name(const MountainData* data, int count, const char* name) {
+    for (int i = 0; i < count; i++) {
+        if (strcmp(data[i].name, name) == 0) {
+            return i;
+        }
+    }
+    return -1;
+}
+
+int main(void) {
+    unsigned n;
+    scanf("%n", &n);
+    MountainData* data = (MountainData*)malloc(sizeof(MountainData) * n);
+    for (unsigned i = 0; i < n; i++) {
+        data[i] = mntn_input();
+    }
+
+    char name_buf[MAX_NAME_SIZE];
+    scanf("%s", name_buf);
+
+    int index = mntn_find_by_name(data, n, name_buf);
+    if (index >= 0) {
+        printf("h: %lf\n", data[index].height);
+    }
+
+    for (unsigned i = 0; i < n; i++) {
+        free((void*)data[i].name);
+    }
+    free(data);
+}
\ No newline at end of file
diff --git a/lab9/t6d.c b/lab9/t6d.c
new file mode 100644
index 0000000..fc8b977
--- /dev/null
+++ b/lab9/t6d.c
@@ -0,0 +1,47 @@
+#include <stdio.h>
+#include <string.h>
+
+struct Seminar {
+    char subject[100];
+    char instructor[100];
+    int groupNumber;
+    char dayOfWeek[20];
+    int hours;
+    char classroom[20];
+};
+
+void inputSeminar(struct Seminar *seminar) {
+    printf("subject: ");
+    scanf("%s", seminar->subject);
+
+    printf("Prof: ");
+    scanf("%s", seminar->instructor);
+
+    printf("Group: ");
+    scanf("%d", &(seminar->groupNumber));
+
+    printf("Day: ");
+    scanf("%s", seminar->dayOfWeek);
+
+    printf("Hours: ");
+    scanf("%d", &(seminar->hours));
+
+    printf("class: ");
+    scanf("%s", seminar->classroom);
+}
+
+int main() {
+    struct Seminar mySeminar;
+
+    inputSeminar(&mySeminar);
+
+    printf("\nData:\n");
+    printf("subject: %s\n", mySeminar.subject);
+    printf("Prof: %s\n", mySeminar.instructor);
+    printf("Group: %d\n", mySeminar.groupNumber);
+    printf("Day: %s\n", mySeminar.dayOfWeek);
+    printf("Hours: %d\n", mySeminar.hours);
+    printf("Class: %s\n", mySeminar.classroom);
+
+    return 0;
+}