Add code source blocks to the chapter Graph.

Fix "函数" and "方法"

codes/c/chapter_heap/my_heap.c

@@ -20,7 +20,7 @@ void siftDown(maxHeap *h, int i);
 
 void siftUp(maxHeap *h, int i);
 
-/* 构造函数，根据切片建堆 */
+/* 构造方法，根据切片建堆 */
 maxHeap *newMaxHeap(int nums[], int size) {
     // 所有元素入堆
     maxHeap *h = (maxHeap *) malloc(sizeof(maxHeap));