chore: initial commit

.gitignore

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+cmake-build-*
+build/
+.idea/

CMakeLists.txt

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+cmake_minimum_required(VERSION 3.26)
+project(advent_of_code_2023 C)
+
+set(CMAKE_C_STANDARD 11)
+
+add_executable(advent_of_code_2023 main.c
+        main.h
+        day_1.c
+        array_list.c
+        array_list.h)

array_list.c

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+//
+// Created by Lennart on 02/12/2023.
+//
+
+#include <stdlib.h>
+
+#include "array_list.h"
+
+array_list* alist_create(int capacity) {
+    array_list *alist = malloc(sizeof (struct array_list_struct));
+    alist->data = malloc(sizeof (ELEMENT_TYPE) * capacity);
+    alist->capacity = capacity;
+    alist->length = 0;
+    return alist;
+}
+
+void alist_add(array_list *alist, ELEMENT_TYPE entry) {
+    if(alist->length >= alist->capacity) {
+        alist->data = realloc(alist->data, alist->capacity * 2);
+        alist->capacity = alist->capacity * 2;
+    }
+
+    alist->data[alist->length++] = entry;
+}
+
+void alist_free(array_list *alist) {
+    free(alist->data);
+    free(alist);
+}

array_list.h

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+//
+// Created by Lennart on 02/12/2023.
+//
+
+#ifndef ADVENT_OF_CODE_2023_ARRAY_LIST_H
+
+#ifndef ELEMENT_TYPE
+#define ELEMENT_TYPE int
+#endif
+
+typedef struct array_list_struct {
+    ELEMENT_TYPE *data;
+    int capacity;
+    int length;
+} array_list;
+
+array_list* alist_create(int capacity);
+
+void alist_add(array_list *alist, ELEMENT_TYPE entry);
+
+void alist_free(array_list *alist);
+
+#define ADVENT_OF_CODE_2023_ARRAY_LIST_H
+
+#endif //ADVENT_OF_CODE_2023_ARRAY_LIST_H

day_1.c

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+//
+// Created by Lennart on 02/12/2023.
+//
+
+#include <stdio.h>
+#include "main.h"
+
+int read_line(FILE *f);
+
+int day_1() {
+    FILE *f = fopen("day_1.txt", "r");
+    if(f == NULL) {
+        printf("Error! Missing input file!");
+        return -1;
+    }
+
+    int sum = 0;
+    while(!feof(f)) {
+        sum += read_line(f);
+    }
+
+    fclose(f);
+    printf("Result: %i\n", sum);
+    return 0;
+}
+
+// Read all digits form the next line in a file
+int read_line(FILE *f) {
+    int first = -1, last = 10; // Use first=-1 to detect unset value and last=10 to return 0 (-10 + 10) when no values are set
+    char buffer[16];
+    int digit;
+    do {
+        fgets(&buffer[0], 16, f);
+        for(int i = 0; i < 16; i++) {
+            if(buffer[i] == '\n') {
+                goto result;
+            } else if(buffer[i] == 0) {
+                break; // End of buffer
+            }
+            if(sscanf(&buffer[i], "%1d", &digit) == 1) { // NOLINT(*-err34-c)
+                if(first == -1) {
+                    first = digit;
+                }
+                last = digit;
+            }
+        }
+    } while(!feof(f));
+
+    result:
+    return first * 10 + last;
+}

main.c

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+#include <stdio.h>
+#include <stdlib.h>
+#include "main.h"
+
+int main(int argc, char **argv) {
+    if(argc <= 1) {
+        printf("Please launch with a day number argument!\n");
+        return -1;
+    }
+
+    int day = (int) strtol(argv[1], (char**) NULL, 10);
+    switch (day) {
+        case 1:
+            return day_1();
+        default:
+            printf("Unknown day: %i", day);
+    }
+
+    return 0;
+}

main.h

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+//
+// Created by Lennart on 02/12/2023.
+//
+
+#ifndef ADVENT_OF_CODE_2023_MAIN_H
+
+int day_1();
+
+#define ADVENT_OF_CODE_2023_MAIN_H
+
+#endif //ADVENT_OF_CODE_2023_MAIN_H