From 0aed24179b3a6c427e166af331db3ef3705942fe Mon Sep 17 00:00:00 2001
From: ElectronixTM <ElectronixTM@noemail.inkling.su>
Date: Wed, 22 Oct 2025 15:52:47 +0300
Subject: [PATCH] feat: libraries lab complete

---
 OSs/lab-libs/Makefile | 22 +++++++++++++++++++++
 OSs/lab-libs/lib.c    | 45 +++++++++++++++++++++++++++++++++++++++++++
 OSs/lab-libs/lib.h    | 21 ++++++++++++++++++++
 OSs/lab-libs/main.c   | 17 ++++++++++++++++
 4 files changed, 105 insertions(+)
 create mode 100644 OSs/lab-libs/Makefile
 create mode 100644 OSs/lab-libs/lib.c
 create mode 100644 OSs/lab-libs/lib.h
 create mode 100644 OSs/lab-libs/main.c

diff --git a/OSs/lab-libs/Makefile b/OSs/lab-libs/Makefile
new file mode 100644
index 0000000..3e7c0bc
--- /dev/null
+++ b/OSs/lab-libs/Makefile
@@ -0,0 +1,22 @@
+all: dynamic static
+
+dynamic: main.o lib.so
+	gcc $^ -o $@ $(CFLAGS) -lm
+
+static: main.o lib.a
+	gcc $^ -o $@ $(CFLAGS) -lm
+
+lib.so: lib.o
+	gcc -shared $^ -o $@ $(CFLAGS)
+
+lib.a: lib.o
+	ar r $@ $^
+
+main.o: main.c
+	gcc -c $^ -o $@ $(CFLAGS)
+
+lib.o: lib.c
+	gcc -c -o $@ -fPIC $^ $(CFLAGS)
+
+clean:
+	rm -f dynamic static *.so *.o
diff --git a/OSs/lab-libs/lib.c b/OSs/lab-libs/lib.c
new file mode 100644
index 0000000..65d2e37
--- /dev/null
+++ b/OSs/lab-libs/lib.c
@@ -0,0 +1,45 @@
+#include "lib.h"
+
+#include <math.h>
+
+#define ZEROIN_MAX_ITERATIONS 1000
+
+size_t fibo(size_t n)
+{
+    size_t prev = 0, cur = 1, tmp = 0;
+    for (size_t i = 0; i < n; i++) {
+        tmp = cur;
+        cur = cur + prev;
+        prev = tmp;
+    }
+    return cur;
+}
+
+double zeroin(double (*f)(double), double err, double a, double b)
+{
+    double left = f(a);
+    if (fabs(left) < err) return left;
+    double right = f(b);
+    if (fabs(right) < err) return right;
+    if (left * right > 0) {
+        return NAN;
+    }
+
+    double x = NAN;
+    double cur = NAN;
+    size_t n = 0;
+    do {
+        x = (a + b) / 2;
+        cur = f(x);
+        if (cur * left > 0) {
+            left = cur;
+            a = x;
+        }
+        else {
+            right = cur;
+            b = x;
+        }
+        n++;
+    } while (fabs(cur) > err || n < ZEROIN_MAX_ITERATIONS);
+    return x;
+}
diff --git a/OSs/lab-libs/lib.h b/OSs/lab-libs/lib.h
new file mode 100644
index 0000000..eebb419
--- /dev/null
+++ b/OSs/lab-libs/lib.h
@@ -0,0 +1,21 @@
+#ifndef LIB_H_
+#define LIB_H_
+
+#include <stdlib.h>
+
+/**
+ * Это будет просто какая-то не очень умная библиотечка с двумя функциями,
+ * просто чтобы их типа собрать
+ */
+
+/**
+ * Считает n-ное число фибоначи
+ */
+size_t fibo(size_t n);
+
+/**
+ * Считает ноль функции на интервале с указанной погрешностью
+ */
+double zeroin(double (*f)(double), double err, double a, double b);
+
+#endif
diff --git a/OSs/lab-libs/main.c b/OSs/lab-libs/main.c
new file mode 100644
index 0000000..9e61317
--- /dev/null
+++ b/OSs/lab-libs/main.c
@@ -0,0 +1,17 @@
+#include <stdio.h>
+#include <math.h>
+#include "lib.h"
+
+#define FIBO_NUM 15
+
+#define SIN_A 1.6
+#define SIN_B 3.7
+#define ZEROIN_ERR 0.001
+
+int main()
+{
+    printf("fibonachi number under index %u: %zu\n", FIBO_NUM, fibo(FIBO_NUM));
+    printf("zero of sin(x) in interval (%lf %lf) is %lf\n",
+            SIN_A, SIN_B, zeroin(sin, ZEROIN_ERR, SIN_A, SIN_B));
+    return 0;
+}