Add List_count()

src/list.c

@@ -219,6 +219,23 @@ int List_extend(List *list_to_extend, List *input_list) {
     return 0;
 }
 
+int List_count(List *list, int element) {
+    if (!list) {
+        return 1;
+    }
+
+    int count = 0;
+    int listLength = List_length(list);
+
+    for (int i = 0; i < listLength; i++) {
+        if (element == List_get(list, i)) {
+            count++;
+        }
+    }
+
+    return count;
+}
+
 int List_length(List *list) {
     return list->_currentSize + 1;
 }

src/test/test.c

@@ -241,6 +241,21 @@ void shouldPopElementFromList() {
     printSuccess(__func__);
 }
 
+void shouldCountElementsInList() {
+    // Arrange
+    List *list = List_new();
+    List_append_all(list, 5, 0, 1, 1, 3, 4, 5);
+
+    // Act
+    int count = List_count(list, 1);
+
+    // Assert
+    assert(count == 2);
+
+    List_destroy(&list);
+    printSuccess(__func__);
+}
+
 int main() {
     printf("============================================");
     printf("\nSTART TESTING");
@@ -258,6 +273,7 @@ int main() {
     shouldExtendList();
     shouldDeleteElementFromList();
     shouldPopElementFromList();
+    shouldCountElementsInList();
     printf("\n\n============================================");
     printf("\nFINISH TESTING");
     printf("\n============================================");