diff --git a/codes/c/chapter_hashing/array_hash_map.c b/codes/c/chapter_hashing/array_hash_map.c
index cb2d8a905..3853ef00b 100644
--- a/codes/c/chapter_hashing/array_hash_map.c
+++ b/codes/c/chapter_hashing/array_hash_map.c
@@ -92,7 +92,7 @@ void pairSet(ArrayHashMap *hmap, MapSet *set) {
     for (i = 0; i < HASHTABLE_CAPACITY; i++) {
         if (hmap->buckets[i] != NULL) {
             entries[index].key = hmap->buckets[i]->key;
-            entries[index].val = malloc(strlen(hmap->buckets[i]->val + 1));
+            entries[index].val = malloc(strlen(hmap->buckets[i]->val) + 1);
             strcpy(entries[index].val, hmap->buckets[i]->val);
             index++;
         }
diff --git a/codes/c/chapter_sorting/counting_sort.c b/codes/c/chapter_sorting/counting_sort.c
index 73ba54f0a..54aed970a 100644
--- a/codes/c/chapter_sorting/counting_sort.c
+++ b/codes/c/chapter_sorting/counting_sort.c
@@ -18,7 +18,7 @@ void countingSortNaive(int nums[], int size) {
     }
     // 2. 统计各数字的出现次数
     // counter[num] 代表 num 的出现次数
-    int *counter = malloc(sizeof(int) * m);
+    int *counter = calloc(m, sizeof(int));
     for (int i = 0; i < size; i++) {
         counter[nums[i]]++;
     }
@@ -29,6 +29,9 @@ void countingSortNaive(int nums[], int size) {
             nums[i] = num;
         }
     }
+
+    // 4. 释放内存
+    free(counter);
 }
 
 /* 计数排序 */
@@ -43,7 +46,7 @@ void countingSort(int nums[], int size) {
     }
     // 2. 统计各数字的出现次数
     // counter[num] 代表 num 的出现次数
-    int *counter = malloc(sizeof(int) * m);
+    int *counter = calloc(m, sizeof(int));
     for (int i = 0; i < size; i++) {
         counter[nums[i]]++;
     }
@@ -62,6 +65,9 @@ void countingSort(int nums[], int size) {
     }
     // 使用结果数组 res 覆盖原数组 nums
     memcpy(nums, res, size * sizeof(int));
+
+    // 5. 释放内存
+    free(counter);
 }
 
 /* Driver Code */