some c solutions

c/euler.c

@@ -0,0 +1,5 @@
+#include <stdio.h>
+
+void print_result(int result) {
+  printf("%d\n", result);
+}

c/euler.h

@@ -0,0 +1 @@
+void print_result(int result);

c/euler001.c

@@ -0,0 +1,14 @@
+#include "euler.h"
+
+int main()
+{
+  int sum = 0;
+  for (int i = 0; i < 1000; i++) {
+    if (i % 3 == 0 || i % 5 == 0) {
+      sum += i;
+    }
+  }
+
+  print_result(sum);
+  return 0;
+}

c/euler002.c

@@ -0,0 +1,29 @@
+#include "euler.h"
+#include "int_list.h"
+#include <stdio.h>
+
+int_list *fibonacci_until(int num)
+{
+
+  static int_list list;
+  int_list_init(&list);
+
+  int term_one = 1;
+  int term_two = 2;
+  while (term_one < num)
+  {
+    if (term_one % 2 == 0) { int_list_add(&list, term_one); }
+    int temp = term_two;
+    term_two = term_two + term_one;
+    term_one = temp;
+  }
+  return &list;
+}
+
+int main()
+{
+  int_list *result;
+  result = fibonacci_until(4000000);
+  print_result(int_list_sum(result));
+  return 0;
+}

c/int_list.c

@@ -0,0 +1,82 @@
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include "int_list.h"
+
+void int_list_init(int_list *l) {
+  l->data = NULL;
+  l->size = 0;
+  l->count = 0;
+}
+
+int int_list_count(int_list *l) {
+  return l->count;
+}
+
+void int_list_add(int_list *l, int value) {
+  if (l->size == 0) {
+    l->size = 10;
+    l->data = malloc(sizeof(int*) * l->size);
+    memset(l->data, '\0', sizeof(int*) * l->size);
+  }
+
+  if (l->size == l->count) {
+    l->size *= 2;
+    l->data = realloc(l->data, sizeof(int*) * l->size);
+  }
+
+  l->data[l->count] = value;
+  l->count++;
+}
+
+int int_list_get(int_list *l, int index) {
+  if (index >= l->count) {
+    printf("error: index out of range");
+    return 0;
+  }
+
+  return l->data[index];
+}
+
+void int_list_set(int_list *l, int index, int value) {
+  if (index >= l->count) {
+    printf("error: index out of range");
+    return;
+  }
+
+  l->data[index] = value;
+}
+
+void int_list_delete(int_list *l, int index) {
+  if (index >= l->count) {
+    printf("error: index out of range");
+    return;
+  }
+
+  int j = index;
+  for (int i = index; i < l->count; i++) {
+    l->data[j] = l->data[i];
+    j++;
+  }
+
+  l->count--;
+}
+
+int int_list_sum(int_list *l) {
+  int sum = 0;
+  for (int i = 0; i < l->count; i++) {
+    sum += (l->data[i]);
+  }
+  return sum;
+}
+
+void int_list_print(int_list *l) {
+  for (int i = 0; i < l->count; i++) {
+    printf("%d ", (l->data[i]));
+  }
+  printf("\n");
+}
+
+void int_list_free(int_list *l) {
+  free(l->data);
+}

c/int_list.h

@@ -0,0 +1,20 @@
+#ifndef INT_LIST_H_
+#define INT_LIST_H_
+
+typedef struct int_list_ {
+  int* data;
+  int size;
+  int count;
+} int_list;
+
+void int_list_init(int_list *l);
+int int_list_count(int_list *l);
+void int_list_add(int_list *l, int value);
+int int_list_get(int_list *l, int index);
+void int_list_set(int_list*l, int index, int value);
+void int_list_delete(int_list *l, int index);
+int int_list_sum(int_list *l);
+void int_list_print(int_list *l);
+void int_list_free(int_list *l);
+
+#endif