diff --git a/week01/ex4 b/week01/ex4
index d913823..0efc61a 100755
Binary files a/week01/ex4 and b/week01/ex4 differ
diff --git a/week02/.clang-format b/week02/.clang-format
new file mode 100644
index 0000000..5bf2f83
--- /dev/null
+++ b/week02/.clang-format
@@ -0,0 +1,2 @@
+BasedOnStyle: LLVM
+IndentWidth: 4
\ No newline at end of file
diff --git a/week02/ex1 b/week02/ex1
new file mode 100755
index 0000000..0bb6ad4
Binary files /dev/null and b/week02/ex1 differ
diff --git a/week02/ex1.c b/week02/ex1.c
new file mode 100644
index 0000000..a2323aa
--- /dev/null
+++ b/week02/ex1.c
@@ -0,0 +1,19 @@
+#include <float.h>
+#include <limits.h>
+#include <stdio.h>
+
+int main() {
+    int i = INT_MAX;
+    unsigned short us = USHRT_MAX;
+    long l = LONG_MAX;
+    float f = FLT_MAX;
+    double d = DBL_MAX;
+
+    printf("int: %lu, %d\n"
+           "unsigned short: %lu, %hu\n"
+           "long: %lu, %ld\n"
+           "float: %lu, %f\n"
+           "double: %lu, %lf\n",
+           sizeof(i), i, sizeof(us), us, sizeof(l), l, sizeof(f), f, sizeof(d),
+           d);
+}
\ No newline at end of file
diff --git a/week02/ex1.sh b/week02/ex1.sh
new file mode 100755
index 0000000..d554831
--- /dev/null
+++ b/week02/ex1.sh
@@ -0,0 +1,4 @@
+#!/bin/sh
+
+gcc ex1.c -o ex1
+./ex1
\ No newline at end of file
diff --git a/week02/ex2 b/week02/ex2
new file mode 100755
index 0000000..2f03a04
Binary files /dev/null and b/week02/ex2 differ
diff --git a/week02/ex2.c b/week02/ex2.c
new file mode 100644
index 0000000..7538e42
--- /dev/null
+++ b/week02/ex2.c
@@ -0,0 +1,18 @@
+#include <stdio.h>
+#include <string.h>
+
+int main() {
+    char s[257], c;
+    int i = 0;
+    while ((c = getc(stdin)) != '.') {
+        if (c == '\n')
+            break;
+        s[i++] = c;
+    }
+    s[i] = '\0';
+    // i is already the size of s. I've used strlen to follow the 'hints'
+    // section.
+    for (i = strlen(s) - 1; i >= 0; --i) {
+        putc(s[i], stdout);
+    }
+}
\ No newline at end of file
diff --git a/week02/ex2.sh b/week02/ex2.sh
new file mode 100755
index 0000000..49e4f0d
--- /dev/null
+++ b/week02/ex2.sh
@@ -0,0 +1,4 @@
+#!/bin/sh
+
+gcc ex2.c -o ex2
+./ex2
\ No newline at end of file
diff --git a/week02/ex3 b/week02/ex3
new file mode 100755
index 0000000..3245d8e
Binary files /dev/null and b/week02/ex3 differ
diff --git a/week02/ex3.c b/week02/ex3.c
new file mode 100644
index 0000000..7572bec
--- /dev/null
+++ b/week02/ex3.c
@@ -0,0 +1,54 @@
+#include <stdio.h>
+#include <string.h>
+
+/* DISCLAIMER: As far as I understand, I need to create a function,
+   which takes a long long number (not a string), convert it to a
+   string, use that string as it was a number in the source
+   number system, and then print out in the target number system.
+
+   I think it is way better to use string for the number itself and
+   read it as a string from the beginning. But I will follow the
+   assignment instructions since I don't want to get a lower grade.
+   Please, make it more clear next time.
+   */
+
+void convert(long long n, int s, int t) {
+    if (!(s >= 2 && s <= 10 && t >= 2 && t <= 10)) {
+        printf("cannot convert!\n");
+        return;
+    }
+
+    // convert n from source number system to normal long long integer
+    long long n_actual = 0, cur = 1;
+    while (n) {
+        if (n % 10 >= s) {
+            printf("cannot convert!\n");
+            return;
+        }
+        n_actual += cur * (n % 10);
+        cur *= s;
+        n /= 10;
+    }
+
+    // convert the actual n to target number system
+    char buf[65];
+    int i = 0;
+    while (n_actual) {
+        buf[i++] = (n_actual % t) + '0';
+        n_actual /= t;
+    }
+    buf[i] = '\0';
+
+    for (--i; i >= 0; --i) {
+        putc(buf[i], stdout);
+    }
+
+    putc('\n', stdout);
+}
+
+int main() {
+    long long number;
+    int source, target;
+    scanf("%lld%d%d", &number, &source, &target);
+    convert(number, source, target);
+}
\ No newline at end of file
diff --git a/week02/ex3.sh b/week02/ex3.sh
new file mode 100755
index 0000000..482c6bd
--- /dev/null
+++ b/week02/ex3.sh
@@ -0,0 +1,4 @@
+#!/bin/sh
+
+gcc ex3.c -o ex3
+./ex3
\ No newline at end of file
diff --git a/week02/ex4 b/week02/ex4
new file mode 100755
index 0000000..a42c2f9
Binary files /dev/null and b/week02/ex4 differ
diff --git a/week02/ex4.c b/week02/ex4.c
new file mode 100644
index 0000000..797a2f0
--- /dev/null
+++ b/week02/ex4.c
@@ -0,0 +1,28 @@
+#include <ctype.h>
+#include <stdio.h>
+#include <string.h>
+
+int count(char s[], char c) {
+    int cnt = 0, sz = strlen(s);
+    for (int i = 0; i < sz; ++i) {
+        if (tolower(s[i]) == tolower(c))
+            cnt++;
+    }
+
+    return cnt;
+}
+
+void countAll(char s[]) {
+    int sz = strlen(s);
+    for (int i = 0; i < sz; ++i) {
+        int cnt = count(s, s[i]);
+        if (cnt > 0)
+            printf("%c:%d%s", tolower(s[i]), cnt, (i == sz - 1 ? "\n" : ", "));
+    }
+}
+
+int main() {
+    char s[257];
+    scanf("%s", s);
+    countAll(s);
+}
\ No newline at end of file
diff --git a/week02/ex4.sh b/week02/ex4.sh
new file mode 100755
index 0000000..7c5306b
--- /dev/null
+++ b/week02/ex4.sh
@@ -0,0 +1,4 @@
+#!/bin/sh
+
+gcc ex4.c -o ex4
+./ex4
\ No newline at end of file
diff --git a/week02/ex5 b/week02/ex5
new file mode 100755
index 0000000..74b5561
Binary files /dev/null and b/week02/ex5 differ
diff --git a/week02/ex5.c b/week02/ex5.c
new file mode 100644
index 0000000..4c9995c
--- /dev/null
+++ b/week02/ex5.c
@@ -0,0 +1,21 @@
+#include <stdio.h>
+
+long long tribonacci(int n) {
+    long long a = 0, b = 1, c = 1;
+    if (n == 0)
+        return a;
+    if (n == 1)
+        return b;
+    if (n == 2)
+        return c;
+
+    for (int i = 3; i <= n; ++i) {
+        long long d = a + b + c;
+        a = b, b = c, c = d;
+    }
+    return c;
+}
+
+int main() {
+    printf("%lld\n%lld\n", tribonacci(4), tribonacci(36));
+}
\ No newline at end of file
diff --git a/week02/ex5.sh b/week02/ex5.sh
new file mode 100755
index 0000000..d924681
--- /dev/null
+++ b/week02/ex5.sh
@@ -0,0 +1,4 @@
+#!/bin/sh
+
+gcc ex5.c -o ex5
+./ex5
\ No newline at end of file
diff --git a/week02/ex6 b/week02/ex6
new file mode 100755
index 0000000..dc33eb8
Binary files /dev/null and b/week02/ex6 differ
diff --git a/week02/ex6.c b/week02/ex6.c
new file mode 100644
index 0000000..4359552
--- /dev/null
+++ b/week02/ex6.c
@@ -0,0 +1,58 @@
+#include <stdio.h>
+
+void triangle(int n) {
+    for (int i = 1; i <= n; ++i) {
+        for (int j = 1; j <= n - i; ++j)
+            printf(" ");
+
+        for (int j = 1; j <= i * 2 - 1; ++j) {
+            printf("*");
+        }
+        printf("\n");
+    }
+}
+
+void triangle2(int n) {
+    for (int i = 1; i <= n; ++i) {
+        for (int j = 1; j <= i; ++j) {
+            printf("*");
+        }
+        printf("\n");
+    }
+}
+
+void arrow(int n) {
+    for (int i = 1; i <= (n + 1) / 2; ++i) {
+        for (int j = 1; j <= i; ++j) {
+            printf("*");
+        }
+        printf("\n");
+    }
+    for (int i = n / 2; i >= 1; --i) {
+        for (int j = 1; j <= i; ++j) {
+            printf("*");
+        }
+        printf("\n");
+    }
+}
+
+void rectangle(int n, int m) {
+    for (int i = 0; i < n; ++i) {
+        for (int j = 0; j < m; ++j) {
+            printf("*");
+        }
+        printf("\n");
+    }
+}
+
+int main() {
+    int n;
+    printf("Specify number of rows: ");
+    scanf("%d", &n);
+    // triangle(n);
+    triangle2(n);
+    printf("\n");
+    arrow(n);
+    printf("\n");
+    rectangle(n, n);
+}
\ No newline at end of file
diff --git a/week02/ex6.sh b/week02/ex6.sh
new file mode 100755
index 0000000..1ef5ed3
--- /dev/null
+++ b/week02/ex6.sh
@@ -0,0 +1,4 @@
+#!/bin/sh
+
+gcc ex6.c -o ex6
+./ex6
\ No newline at end of file