voidptrdance

commit 75986f1a7c5169f0d736f2b34bcd88dd30da1d69
parent a8ad2d8a2fba1f8c51095f5ee8a361de130a3ed4
Author: Sebastiano Tronto <sebastiano@tronto.net>
Date:   Sat, 25 Feb 2023 23:44:39 +0100

Added some code

Diffstat:
A
PriorityQueue/PriorityQueue.c
 | 
35
+++++++++++++++++++++++++++++++++++
M
PriorityQueue/PriorityQueue.h
 | 
7
+------
A
PriorityQueue/a.out
 | 
0

A
PriorityQueue/main1.c
 | 
14
++++++++++++++
A
PriorityQueue/main2.c
 | 
25
+++++++++++++++++++++++++
M
README.md
 | 
3
+++

6 files changed, 78 insertions(+), 6 deletions(-)
diff --git a/PriorityQueue/PriorityQueue.c b/PriorityQueue/PriorityQueue.c
@@ -0,0 +1,35 @@
+#include <stdlib.h>
+#include "PriorityQueue.h"
+
+typedef struct {
+	T e[255];
+	int n;
+} QData;
+
+PriorityQueue *NewPriorityQueue(TDescription desc) {
+	PriorityQueue *q = malloc(sizeof(PriorityQueue));
+	q->desc = desc;
+	q->data = malloc(sizeof(QData));
+	((QData *)q->data)->n = 0;
+	return q;
+}
+
+void Add(PriorityQueue *q, T t) {
+	QData *qdata = (QData *)q->data;
+	qdata->e[qdata->n++] = t;
+}
+	
+T Pop(PriorityQueue *q) {
+	QData *qdata = (QData *)q->data;
+	if (qdata->n == 0) return NULL;
+	int i, itop = 0;
+	for (i = 0; i < qdata->n; i++)
+		if (q->desc.priority(qdata->e[i]) >
+		    q->desc.priority(qdata->e[itop]))
+			itop = i;
+	T top = qdata->e[itop];
+	for (int j = i; j < qdata->n-1; j++)
+		qdata->e[j] = qdata->e[j+1];
+	qdata->n--;
+	return top;
+}
diff --git a/PriorityQueue/PriorityQueue.h b/PriorityQueue/PriorityQueue.h
@@ -1,18 +1,13 @@
-/* TODO: maybe v1 with exposed priority queue data, then v2 with
-	just void * to better encapsulate? */
-
 typedef void * T;
 typedef struct {
 	int (*priority)(T);
-	char *ToString(T);
 } TDescription;
 
 typedef struct {
+	TDescription desc;
 	void *data;
-	TDescription;
 } PriorityQueue;
 
 PriorityQueue *NewPriorityQueue(TDescription);
 void Add(PriorityQueue *, T);
 T Pop(PriorityQueue *);
-void DeletePriorityQueue(PriorityQueue *);
diff --git a/PriorityQueue/a.out b/PriorityQueue/a.out
Binary files differ.
diff --git a/PriorityQueue/main1.c b/PriorityQueue/main1.c
@@ -0,0 +1,14 @@
+#include <stdio.h>
+#include "PriorityQueue.h"
+
+int priority_int(void *i) { return *(int *)i; }
+TDescription int_desc = { .priority = priority_int };
+
+int main() {
+	PriorityQueue *q = NewPriorityQueue(int_desc);
+	int x = -12, y = 42;
+	Add(q, &x);
+	Add(q, &y);
+	printf("The highest-priority element is %d\n", *(int *)Pop(q));
+	return 0;
+}
diff --git a/PriorityQueue/main2.c b/PriorityQueue/main2.c
@@ -0,0 +1,25 @@
+#include <stdio.h>
+#include <string.h>
+#include "PriorityQueue.h"
+
+int count_stars(void *v) {
+	char *s = (char *)v;
+	int i = 0;
+	while (i < strlen(s) && s[i] == '*') i++;
+	return i;
+}
+TDescription str_desc = { .priority = count_stars };
+
+int main() {
+	PriorityQueue *q = NewPriorityQueue(str_desc);
+	char *s = "Boring task";
+	char *t = "* Eat dinner";
+	char *u = "**** Write blog post!";
+	Add(q, s);
+	Add(q, t);
+	Add(q, u);
+	char *first = Pop(q);
+	char *second = Pop(q);
+	printf("First thing to do is '%s', followed by '%s'\n", first, second);
+	return 0;
+}
diff --git a/README.md b/README.md
@@ -1 +1,4 @@
 Just some code for a future blog post (stay tuned!)
+
+TODO: add ToString function to TDescription and use it to print?
+Add also ToString for PriorityQueue. ToString for tasks should remove stars.