From a470c304199866aa1f3d39ff22ec30734f03d617 Mon Sep 17 00:00:00 2001
From: justanothercatgirl <sotov@twistea.su>
Date: Fri, 6 Dec 2024 15:08:31 +0300
Subject: сделал 8 задание))))
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---
 main.c | 89 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 89 insertions(+)
 create mode 100644 main.c

(limited to 'main.c')

diff --git a/main.c b/main.c
new file mode 100644
index 0000000..01e5ef7
--- /dev/null
+++ b/main.c
@@ -0,0 +1,89 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <diffeq.h>
+#include <equations.h>
+#include <types.h>
+
+#define neqs 4
+eqf_t eqfs[] = {f1, f2, f3, f4};
+
+void help(const char *program, int exit_code) {
+	printf("Usage:\n%s --method euler|rk4 [--equations <integer>] [--files <f1 f2 ... fn>] [--dt <number>] [--interval <start> <end>] [--init <num1 num2 ... num_n>]\n", program);
+	puts(	"\t--method, -m:\twhich method to use, euler's method or 4th order Runge-Kutta method. Default: euler\n"
+		"\t--equations, -e:\tAmount of equations. Optional, default 4\n"
+		"\t--files, -f:\tSpecifies output files for approximations. Default: f1.data, f2.data, ...\n"
+		"\t--dt, -t:\tApproximation step. default 0.1\n"
+		"\t--range, -r:\tInterval of an approximation. defaults to '0 40'\n"
+		"\t--init, -i:\tInitial conditions for problem at the start of an interval. Default: '0.1 -0.1 0.1 -0.1' ...\n"
+		"\t--help, -h:\tThis message\n\n"
+		"Note: -e MUST come before -f and -i. If not done so, amount of files will be determined incorrectly"
+	);
+	if (exit_code < 0) return;
+	else exit(exit_code);
+}
+
+int main(int argc, char *argv[]) {
+	i32 i, j, numeq = 4;
+	f64 dt = 0.1, start = 0, end = 40;
+	f64 * init = NULL;
+	const char **files = NULL;
+	void (*solver)(eqf_t*, f64*, const char**, usz, f64, f64, f64) = difeq_solve_euler;
+
+	for (i = 1; i < argc; ++i) {
+		if (!strcmp("-h", argv[i]) || !strcmp("--help", argv[i]))
+			help(*argv, 0);
+		if (!strcmp("-e", argv[i]) || !strcmp("--equations", argv[i]))
+			numeq = atoi(argv[++i]);
+		if (!strcmp("-t", argv[i]) || !strcmp("--dt", argv[i]))
+			dt = atof(argv[++i]);
+		if (!strcmp("-r", argv[i]) || !strcmp("--range", argv[i])) {
+			start = atof(argv[++i]);
+			end = atof(argv[++i]);
+		}
+		if (!strcmp("-i", argv[i]) || !strcmp("--init", argv[i])) {
+			init = calloc(numeq, sizeof(f64));
+			for (j = 0; j < numeq; ++j) init[j] = atof(argv[++i]);
+		}
+		if (!strcmp("-f", argv[i]) || !strcmp("--files", argv[i])) {
+			files = calloc(numeq, sizeof(char*));
+			for (j = 0; j < numeq; ++j) files[j] = argv[++i];
+		}
+		if (!strcmp("-m", argv[i]) || !strcmp("--method", argv[i])) {
+			++i;
+			if (!strcmp(argv[i], "euler")) {
+				solver = difeq_solve_euler;
+				continue;
+			} 
+			if (!strcmp(argv[i], "rk4")) {
+				solver = difeq_solve_RK;
+				continue;
+			}
+			printf("\x1b[91mError:\x1b[0mNo such method \"%s\". Available methods: \"euler\"\"rk4\". see --help for details.\n", argv[i]);
+			return EXIT_FAILURE;
+		}
+	}
+	
+	if (numeq != neqs) {
+		printf("\x1b[91mError:\x1b[0mCan not solve more than 4 equations without changing source code of main.");
+		return EXIT_FAILURE;
+	}
+	if (files == NULL) {
+		files = calloc(4, sizeof(char*));
+		files[0] = "f1.data", files[1] = "f2.data",
+		files[2] = "f3.data", files[3] = "f4.data";
+	}
+	if (init == NULL) {
+		init = calloc(4, sizeof (double));
+		init[0] = init[2] = 0.1,
+		init[1] = init[3] = -0.1;
+	}
+
+	solver(eqfs, init, files, neqs, start, end, dt);
+	puts("Done");
+	
+	free(init);
+	free(files);
+	return EXIT_SUCCESS;
+}
-- 
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