initial commit

5 files changed, 258 insertions, 25 deletions

diff --git a/Makefile b/Makefile
index 79b383d..aca0f03 100644
--- a/Makefile
+++ b/Makefile
@@ -1,2 +1,30 @@
-sin: main.c
-	cc -o sin main.c
+
+all: t1_a t1_b t2 test.so
+
+T2FLAGS := -Wall
+
+ifneq ($(OS),Windows_NT)
+	T2FLAGS += -DDYNAMIC_LOAD
+	T2LINKS = -lm -ldl
+	ifneq (, $(shell which gnuplot))
+		T2FLAGS += -DPIPE_GNUPLOT
+	endif
+endif
+
+t1_a: main_1.c
+	$(CC) -DPROG_SINUS_SUM $^ -o $@
+
+t1_b: main_1.c
+	$(CC) -DPROG_MONTE_CARLO $^ -o $@
+
+t2: main_2.c
+	$(CC) $(T2FLAGS) $^ -o $@ $(T2LINKS)
+
+test.so: test_f.c
+	$(CC) -fPIC -fPIE -shared $^ -o $@ 
+
+.PHONY: clean
+
+clean:
+	rm -rf t1_a t1_b t2 test.so
+
diff --git a/main.c b/main.c
deleted file mode 100644
index 74277f0..0000000
--- a/main.c
+++ /dev/null
@@ -1,23 +0,0 @@
-#include <stdio.h>
-
-#define EPSILON	0.001*0.001
-#define MAX_ITERATIONS 100
-
-int main(void) {
-	double x;
-	double result;
-	double last_elem;
-	int i;
-	
-	printf("Input a number\n");
-	scanf("%lf", &x);
-	last_elem = result = x;
-
-	for (i = 1; i < MAX_ITERATIONS; ++i) {
-		last_elem = last_elem * x * x / (2*i * (2*i+1));
-		if (last_elem*last_elem <= EPSILON) break;
-		result += last_elem * ( (i%2 * -2) + 1 );
-	}
-	printf("result = %lf; iterations = %i; last_elem = %lf\n", result, i, last_elem);
-	return 0;
-}
diff --git a/main_1.c b/main_1.c
new file mode 100644
index 0000000..cd84b67
--- /dev/null
+++ b/main_1.c
@@ -0,0 +1,89 @@
+#include <stdio.h>
+
+#if defined(PROG_SINUS_SUM)
+
+#define EPSILON	0.001*0.001
+#define MAX_ITERATIONS 100
+
+int main(void) {
+	puts("defined macro PROG_SINUS_SUM");
+	double x;
+	double result;
+	double last_elem;
+	int i;
+	
+	printf("Input a number\n");
+	scanf("%lf", &x);
+	last_elem = result = x;
+
+	for (i = 1; i < MAX_ITERATIONS; ++i) {
+		last_elem = last_elem * x * x / (2*i * (2*i+1));
+		if (last_elem*last_elem <= EPSILON) break;
+		result += last_elem * ( (i%2 * -2) + 1 );
+	}
+	printf("result = %lf; iterations = %i; last_elem = %lf\n", result, i, last_elem);
+	return 0;
+}
+
+#elif defined(PROG_MONTE_CARLO)
+
+#include <stdlib.h>
+#include <time.h>
+
+#define _USE_MATH_DEFINES
+#include <math.h>
+
+struct point {
+	float x, y;
+};
+
+struct circle {
+	// center not needed for this task
+	/*struct point center;*/
+	float rad;
+};
+
+char in_circle(const struct circle *c, const struct point p) {
+	/*p.x -= c->x;*/
+	/*p.y -= c->y;*/
+	return p.x * p.x + p.y * p.y < c->rad*c->rad;
+}
+
+float calculate_pi(int iterations) {
+	int in = 0, out = 0;
+	int *arr[2] = {&out, &in};
+	const struct circle c = {.rad = 1.0f};
+	for (int i = 0; i < iterations; ++i) {
+		struct point p = {
+			.x = rand() % 2000000u / 1e6f - 1,
+			.y = rand() % 2000000u / 1e6f - 1
+		};
+		++*arr[in_circle(&c, p)];
+	}
+	return (float)in/iterations * 4;
+}
+
+int main(int argc, char *argv[]) {
+	puts("defined macro PROG_MONTE_CARLO");
+	srand(time(NULL));
+	int iters;
+	if (argc == 2) {
+		iters = atoi(argv[1]);
+	} else {
+		fputs("Iterations: ", stdout);
+		if (!scanf("%i", &iters)) {
+			fputs("Input a valid number\n", stderr);
+			return EXIT_FAILURE;
+		}
+	}
+	float pi = calculate_pi(iters);
+	float err = fabs(M_PI-pi)/M_PI;
+	printf(	"calculated pi: %.4f, actual pi: %.4f\n"
+		"error: %.2f%%\n",
+		pi, M_PI, err * 100);
+	return EXIT_SUCCESS;
+}
+
+#else
+	#error "define macro PROG_SINUS_SUM or PROG_MONTE_CARLO in compilation flags"
+#endif
diff --git a/main_2.c b/main_2.c
new file mode 100644
index 0000000..8f6fb71
--- /dev/null
+++ b/main_2.c
@@ -0,0 +1,134 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+
+#ifdef PIPE_GNUPLOT
+	#include <unistd.h>
+	#include <fcntl.h>
+#endif // PIPE_GNUPLOT
+
+#ifdef DYNAMIC_LOAD
+	#include <dlfcn.h>
+void* handle = NULL;
+#endif // DYNAMIC_LOAD
+
+struct dval {
+	double x, y;
+};
+
+typedef double (*func_t)(double);
+
+double sin2(double x) {
+	double y = sin(x);
+	return y*y;
+}
+
+double cos2(double x) {
+	double y = cos(x);
+	return y*y;
+}
+
+double __sincos(double x) {
+	// sin(x)cos(x) = sin(2x)/2
+	return sin(2*x)/2;
+}
+
+struct dval* get_table(func_t f, double start, double end, double step, long *length) {
+	long tlength = lround((end-start)/step);
+	struct dval* vals = calloc(tlength, sizeof(struct dval));
+	for (long i = 0; i < tlength; ++i) {
+		double x = start + step * i;
+		// Not accumulative because if step is too small, 
+		// start will never increment
+		vals[i] = (struct dval){.x = x, .y = f(x)};
+	}
+	*length = tlength;
+	return vals;
+}
+
+void print_help(int status) {
+	const char *help = 
+		"Usage: ./task2 -f func_name -o output_file [-h]\n"
+		"\t-h: this help\n"
+		"\t-f: function: either 'sin2', 'cos2' or 'sincos'.\n"
+		"\t\tif compiled with -DDYNAMIC_LOAD, file name with dynamic function.\n"
+		"\t-o: output file.\n\n"
+		"NOTE: the function in dynamic library must be named 'f'.\n"
+		"NOTE 2: with flag -DPIPE_GNUPLOT output will be piped in gnuplot\n.";
+	puts(help);
+	exit(status);
+}
+
+func_t get_function(const char* name) {
+	if (!strcmp(name, "cos2"))
+		return &cos2;
+	if (!strcmp(name, "sin2"))
+		return &sin2;
+	if (!strcmp(name, "sincos"))
+		return &__sincos;
+#ifndef DYNAMIC_LOAD
+	fputs("ERROR: unknown function. To use dynamic loading, compile with `-DDYNAMIC_LOAD`.\n", stderr);
+	exit(EXIT_FAILURE);
+#else  // DYNAMIC_LOAD
+	handle = dlopen(name, RTLD_NOW);
+	if (!handle) goto fail;
+	func_t f = dlsym(handle, "f");
+	if (!f) goto fail;
+	return f;
+fail:
+	fputs(dlerror(), stderr);
+	exit(EXIT_FAILURE);
+#endif // DYNAMIC_LOAD
+}
+
+void print_table(FILE* stream, const struct dval *table, long size) {
+	for (long i = 0; i < size; ++i) {
+		fprintf(stream, "%lg %lg\n", table[i].x, table[i].y);
+	}
+}
+
+int main(int argc, char *argv[]) {
+	func_t function = NULL;
+	const char *out = NULL;
+	for (int i = 1; i < argc; ++i) {
+		if (!strcmp(argv[i], "-h"))
+			print_help(EXIT_SUCCESS);
+		else if (!strcmp(argv[i], "-f"))
+			function = get_function(argv[++i]);
+		else if (!strcmp(argv[i], "-o"))
+			out = argv[++i];
+		else print_help(EXIT_FAILURE);
+	}
+	if (!function || !out) print_help(EXIT_SUCCESS);
+	long table_len;
+	struct dval *table = get_table(function, 0, 3, 0.01, &table_len);
+	print_table(stdout, table, table_len);
+	FILE *f = fopen(out, "w+");
+	if (f) { 
+		print_table(f, table, table_len);
+		fflush(f);
+	}
+	else perror(out);
+
+#ifdef PIPE_GNUPLOT 
+	FILE* gp = popen("gnuplot", "w");
+	if (!gp) goto exit;
+	fputs("plot '-' with lines\n", gp);
+	print_table(gp, table, table_len);
+	fputs("e\n", gp);
+	fflush(gp);
+
+	getchar();
+	pclose(gp);
+#endif // PIPE_GNUPLOT
+
+exit:
+	fclose(f);
+	free(table);
+#ifdef DYNAMIC_LOAD
+	if (handle) dlclose(handle);
+#endif // DYNAMIC_LOAD
+	exit(EXIT_SUCCESS);
+}
+
diff --git a/test_f.c b/test_f.c
new file mode 100644
index 0000000..8811f1e
--- /dev/null
+++ b/test_f.c
@@ -0,0 +1,5 @@
+double f(double x) {
+	static int counter = 0;
+	++counter;
+	return counter * x;
+}