diff --git a/zad6/.ccls b/zad6/.ccls
new file mode 100644
index 0000000..9f91bd0
--- /dev/null
+++ b/zad6/.ccls
@@ -0,0 +1,21 @@
+gcc
+%c -std=c99
+%h
+-Iinclude
+-Wall
+-Wextra
+-Wpedantic
+-Wstrict-aliasing
+-Wfloat-equal
+-Wundef
+-Wshadow
+-Wpointer-arith
+-Wcast-align
+-Wstrict-prototypes
+-Wstrict-overflow=5
+-Wwrite-strings
+-Wcast-qual
+-Wswitch-default
+-Wswitch-enum
+-Wconversion
+-Wunreachable-code
diff --git a/zad6/Cargo.lock b/zad6/Cargo.lock
new file mode 100644
index 0000000..87a4534
--- /dev/null
+++ b/zad6/Cargo.lock
@@ -0,0 +1,23 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "cc"
+version = "1.0.90"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8cd6604a82acf3039f1144f54b8eb34e91ffba622051189e71b781822d5ee1f5"
+
+[[package]]
+name = "libc"
+version = "0.2.153"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9c198f91728a82281a64e1f4f9eeb25d82cb32a5de251c6bd1b5154d63a8e7bd"
+
+[[package]]
+name = "zad6"
+version = "0.1.0"
+dependencies = [
+ "cc",
+ "libc",
+]
diff --git a/zad6/Cargo.toml b/zad6/Cargo.toml
new file mode 100644
index 0000000..2993348
--- /dev/null
+++ b/zad6/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "zad6"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+libc = "0.2.153"
+
+[build-dependencies]
+cc = "1.0.90"
diff --git a/zad6/build.rs b/zad6/build.rs
new file mode 100644
index 0000000..f8602ff
--- /dev/null
+++ b/zad6/build.rs
@@ -0,0 +1,8 @@
+extern crate cc;
+
+fn main() {
+    cc::Build::new()
+        .file("src/mod_iter.c")
+        .shared_flag(true)
+        .compile("mod.a");
+}
diff --git a/zad6/src/main.rs b/zad6/src/main.rs
new file mode 100644
index 0000000..aa892fc
--- /dev/null
+++ b/zad6/src/main.rs
@@ -0,0 +1,27 @@
+#[repr(C)]
+pub struct Result {
+  pub resultExists: libc::c_int,
+  pub n: libc::c_int,
+  pub m: libc::c_int,
+}
+
+extern "C" {
+    pub fn gcd(a: libc::c_uint, b: libc::c_uint) -> libc::c_uint;
+
+    pub fn factorial(n: libc::c_uint) -> libc::c_uint;
+
+    pub fn diophantine(a: libc::c_int, b: libc::c_int, c: libc::c_int) -> Result;
+}
+
+fn main() {
+    unsafe {
+        println!("gcd(a, b): {}", gcd(10, 5));
+        println!("factorial(a): {}", factorial(5));
+        let r = diophantine(1027, 712, 1);
+        if r.resultExists == 0 {
+            println!("dupa");
+        } else {
+            println!("diophantine(a, b, c): {}, {}", r.n, r.m);
+        }
+    }
+}
diff --git a/zad6/src/mod_iter.c b/zad6/src/mod_iter.c
new file mode 100644
index 0000000..ff6a3c3
--- /dev/null
+++ b/zad6/src/mod_iter.c
@@ -0,0 +1,87 @@
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdlib.h>
+
+unsigned int factorial(unsigned int n) {
+    unsigned int result = 1;
+
+    for (size_t i = 1; i <= n; ++i) {
+        result *= i;
+    }
+
+    return result;
+}
+
+unsigned int gcd(unsigned int a, unsigned int b) {
+    if (a == 0) return b;
+
+    size_t r;
+
+    while (b > 0) {
+        r = a % b;
+
+        a = b;
+        b = r;
+    }
+
+    return a;
+}
+
+int extended_gcd(int a, int b, int *x, int *y) {
+    *x = 1;
+    *y = 0;
+    int x1 = 0;
+    int y1 = 1;
+    int q;
+    int temp_x, temp_y, temp_b;
+    while (b != 0) {
+        q = a / b;
+
+        temp_x = *x - q * x1;
+        temp_y = *y - q * y1;
+        *x = x1;
+        *y = y1;
+        x1 = temp_x;
+        y1 = temp_y;
+
+        temp_b = a - q * b;
+        a = b;
+        b = temp_b;
+    }
+
+    return a;
+}
+
+typedef struct {
+    bool resultExists;
+    int n;
+    int m;
+} Result;
+
+Result diophantine(int a, int b, int c) {
+    Result r = {
+        .resultExists = false,
+        .n = 0,
+        .m = 0,
+    };
+
+    if (a == 0 && b == 0)
+        return r;
+    int x0 = 0;
+    int y0 = 0;
+    int g = extended_gcd(abs(a), abs(b), &x0, &y0);
+
+    if (c % g)
+        return r;
+
+    x0 *= c / g;
+    y0 *= c / g;
+    if (a < 0) x0 = -x0;
+    if (b < 0) y0 = -y0;
+
+    r.resultExists = true;
+    r.n = x0;
+    r.m = y0;
+
+    return r;
+}
diff --git a/zad6/src/mod_rec.c b/zad6/src/mod_rec.c
new file mode 100644
index 0000000..d8ec451
--- /dev/null
+++ b/zad6/src/mod_rec.c
@@ -0,0 +1,68 @@
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+
+unsigned int factorial(unsigned int n) {
+    if (n == 0 || n == 1) {
+        return 1;
+    }
+
+    return n * factorial(n - 1);
+}
+
+unsigned int gcd(unsigned int a, unsigned int b) {
+    if (b == 0) {
+        return a;
+    }
+
+    return gcd(b, a % b);
+}
+
+int extended_gcd(int a, int b, int *x, int *y) {
+    if (b == 0) {
+        *x = 1;
+        *y = 0;
+        return a;
+    }
+    int x1, y1;
+    int d = extended_gcd(b, a % b, &x1, &y1);
+    *x = y1;
+    *y = x1 - y1 * (a / b);
+    return d;
+}
+
+typedef struct {
+    bool resultExists;
+    int n;
+    int m;
+} Result;
+
+Result diophantine(int a, int b, int c) {
+    Result r = {
+        .resultExists = false,
+        .n = 0,
+        .m = 0,
+    };
+
+    if (a == 0 && b == 0)
+        return r;
+    int x0 = 0;
+    int y0 = 0;
+    int g = extended_gcd(abs(a), abs(b), &x0, &y0);
+
+    if (c % g)
+        return r;
+
+    x0 *= c / g;
+    y0 *= c / g;
+    if (a < 0) x0 = -x0;
+    if (b < 0) y0 = -y0;
+
+    r.resultExists = true;
+    r.n = x0;
+    r.m = y0;
+
+    return r;
+}