Implement C arg parsing with getopt_long

README.md

@@ -6,7 +6,7 @@ C port of [SD](https://git.exozy.me/Ta180m/SD), a very efficient flash cards app
 
 Flash cards are stored in the `cards` table of a SQLite database. There are four columns: `idx INTEGER PRIMARY KEY, weight INTEGER, key STRING, val STRING`. The `idx` is a unique index for each card, starting at 0. The weight is how often the card should come up. The key and value are the front and reverse sides of the card. You can use the `sqlite3` CLI to create a card deck.
 
-Now build this project with `gcc cd.c -o cd -O2 -march=native` and run `./cd` to enjoy a fast flash cards experience! The program will display the `key` of a randomly selected card. Press any key to show the `val` of the card. Now press either `y` or `n` depending on whether you got the card correct, and the program adjusts that card's weight.
+Now build this project with `gcc cd.c -o cd -l sqlite3 -O2 -march=native` and run `./cd` to enjoy a fast flash cards experience! The program will display the `key` of a randomly selected card. Press any key to show the `val` of the card. Now press either `y` or `n` depending on whether you got the card correct, and the program adjusts that card's weight.
 
 If you're wondering where the name came from, this is the C port of [SD](https://git.exozy.me/Ta180m/SD).
 

cd.c

@@ -1,7 +1,42 @@
 #include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <unistd.h>
+#include <getopt.h>
 #include <sqlite3.h>
 #include "segmenttree.h"
 
 int main(int argc, char* argv[]) {
-	printf("Hello!");
+	char *file = "cards";
+	bool verbose = false;
+
+	static struct option long_options[] = {
+		{"file",    required_argument, 0, 'f'},
+		{"verbose", no_argument,       0, 'v'}
+	};
+	while (1) {
+		int option_index = 0;
+		int c = getopt_long(argc, argv, "f:v", long_options, &option_index);
+		if (c == -1) break;
+		switch (c) {
+			case 'f': file = strdup(optarg); break;
+			case 'v': verbose = true; break;
+			default: abort();
+		}
+	}
+
+	printf("%s", file);
+
+	sqlite3 *db;
+	int rc = sqlite3_open(file, &db);
+	if (rc) {
+		fprintf(stderr, "Can't open database: %s\n", sqlite3_errmsg(db));
+		abort();
+	}
+	fprintf(stderr, "Opened database successfully\n");
+
+	//int N = sqlite3_exec(db, "SELECT COUNT(*) FROM cards", callback)
+
+	sqlite3_close(db);
 }

segmenttree.c

@@ -0,0 +1,46 @@
+struct SegmentTree {
+	int N;
+	int * seg;
+}
+
+// Build segment tree
+void Build(int l, int r, int n) {
+	if (l == r) {
+	
+	}
+	int m = l + r >> 1;
+	Build(l, m, n << 1);
+	Build(m + 1, r, n << 1 | 1);
+	seg[n] = seg[n << 1] + seg[n << 1 | 1];
+}
+
+// Update value at index x
+void Update(int x, int v, int l, int r, int n) {
+	if (l == r) {
+		seg[n] += v;
+		return;
+	}
+	int m = l + r >> 1;
+	if (x <= m) {
+		Update(x, v, l, m, n<<1);
+	}
+	else {
+		Update(x, v, m+1, r, n<<1|1);
+	}
+	seg[n] = seg[n << 1] + seg[n << 1 | 1];
+}
+
+// Find element with prefix sum v
+int Query(int v, int l, int r, int n) {
+	if (l == r) {
+		return s.seg[n], l;
+	}
+	int m = l + r >> 1;
+	if (seg[n << 1] >= v) {
+		return Query(v, l, m, n << 1);
+	}
+	else {
+		return Query(v - s.seg[n << 1], m + 1, r, n << 1 | 1);
+	}
+}
+