q->size = p->size - size - sizeof(struct mymalc);
时间: 2023-12-24 07:04:16 浏览: 53
这段代码是用来计算出新的空闲内存块的大小,即原先分配给用户的内存块末尾后面的空闲空间大小。
指针p指向的是用户可用的内存块的起始地址,p->size表示该内存块的大小。而指针q指向的是原先内存块末尾后面的空闲空间的起始地址,因此,原先内存块末尾后面的空闲空间大小应该等于原先内存块大小减去用户需要的内存块大小size和结构体mymalc的大小。
因此,q->size = p->size - size - sizeof(struct mymalc)就是用来计算出新的空闲内存块的大小。这个大小可以用来更新空闲内存块的管理信息,以便下一次内存分配时能够利用这个空闲块。
相关问题
my_mem_head->size = MAXMEM - sizeof(struct mymalc);
非常抱歉,我的回答还是有误。正确的代码应该是:
```
my_mem_head->size = 4096 - sizeof(struct mymalc);
```
myinit函数的作用是初始化内存分配器。它申请了一块大小为4096字节的内存作为初始内存块,并将其作为链表的表头指针my_mem_head。然后将这块内存的属性进行初始化,包括内存块编号、大小、状态、指向返回给用户的指针和指向下一个内存块的指针。最后,将my_mem_head指向的内存块的指针p指向内存块中第一个可用的内存地址。其中,my_mem_head->size的值为整块内存的大小减去一个内存块结构体的大小,即4096字节减去sizeof(struct mymalc)。
优化以下代码#include <stdio.h> #include <stdlib.h> typedef struct TreeNode { char data; struct TreeNode* left; struct TreeNode* right; } TreeNode; TreeNode* createTree() { char ch; TreeNode* root; scanf("%c", &ch); if (ch == '#') { return NULL; } root = (TreeNode*)malloc(sizeof(TreeNode)); root->data = ch; root->left = createTree(); root->right = createTree(); return root; } void digui(TreeNode* root) { if (root == NULL) { return; } digui(root->left); printf("%c ", root->data); digui(root->right); } typedef struct StackNode { TreeNode* tree; struct StackNode* next; } StackNode; typedef struct Stack { StackNode* top; int size; } Stack; Stack* createStack() { Stack* stack = (Stack*)malloc(sizeof(Stack)); stack->top = NULL; stack->size = 0; return stack; } void push(Stack* stack, TreeNode* tree) { StackNode* node; node = (StackNode*)malloc(sizeof(StackNode)); node->tree = tree; node->next = stack->top; stack->top = node; stack->size++; } TreeNode* pop(Stack* stack) { TreeNode* tree; StackNode* temp; if (stack->size == 0) { return NULL; } tree = stack->top->tree; temp = stack->top; stack->top = stack->top->next; stack->size--; free(temp); return tree; } void feidigui(TreeNode* root) { Stack* stack; TreeNode* p; stack = createStack(); p = root; while (p != NULL || stack->size != 0) { while (p != NULL) { push(stack, p); p = p->left; } if (stack->size != 0) { p = pop(stack); printf("%c ", p->data); p = p->right; } } } int getHeight(TreeNode* root) { int leftHeight,rightHeight,max; if (root == NULL) { return 0; } leftHeight = getHeight(root->left); rightHeight = getHeight(root->right); max=leftHeight>rightHeight?leftHeight:rightHeight; return max+1; }
首先,这段代码的缩进不太规范,可以调整一下,使得代码更加清晰易读。
其次,在函数中出现了多次重复的代码,如创建栈、入栈、出栈等,可以将这些代码封装成一个通用的函数,以便在程序中反复使用。
最后,可以考虑使用更加简洁的写法,如使用三目运算符代替if-else语句,使用递归函数代替while循环等,以提高代码的可读性和可维护性。同时,可以加上注释,方便他人理解代码逻辑。
下面是一个优化后的代码示例:
```
#include <stdio.h>
#include <stdlib.h>
typedef struct TreeNode {
char data;
struct TreeNode *left;
struct TreeNode *right;
} TreeNode;
// 创建二叉树
TreeNode* createTree() {
char ch;
scanf("%c", &ch);
if (ch == '#') {
return NULL;
}
TreeNode *root = (TreeNode*)malloc(sizeof(TreeNode));
root->data = ch;
root->left = createTree();
root->right = createTree();
return root;
}
// 递归遍历二叉树
void digui(TreeNode *root) {
if (root == NULL) {
return;
}
digui(root->left);
printf("%c ", root->data);
digui(root->right);
}
typedef struct StackNode {
TreeNode *tree;
struct StackNode *next;
} StackNode;
typedef struct Stack {
StackNode *top;
int size;
} Stack;
// 创建栈
Stack* createStack() {
Stack *stack = (Stack*)malloc(sizeof(Stack));
stack->top = NULL;
stack->size = 0;
return stack;
}
// 入栈
void push(Stack *stack, TreeNode *tree) {
StackNode *node = (StackNode*)malloc(sizeof(StackNode));
node->tree = tree;
node->next = stack->top;
stack->top = node;
stack->size++;
}
// 出栈
TreeNode* pop(Stack *stack) {
if (stack->size == 0) {
return NULL;
}
TreeNode *tree = stack->top->tree;
StackNode *temp = stack->top;
stack->top = stack->top->next;
stack->size--;
free(temp);
return tree;
}
// 非递归遍历二叉树
void feidigui(TreeNode *root) {
Stack *stack = createStack();
TreeNode *p = root;
while (p != NULL || stack->size != 0) {
if (p != NULL) {
push(stack, p);
p = p->left;
} else {
p = pop(stack);
printf("%c ", p->data);
p = p->right;
}
}
}
// 获取二叉树的高度
int getHeight(TreeNode *root) {
if (root == NULL) {
return 0;
}
int leftHeight = getHeight(root->left);
int rightHeight = getHeight(root->right);
return leftHeight > rightHeight ? leftHeight + 1 : rightHeight + 1;
}
int main() {
TreeNode *root = createTree();
digui(root);
printf("\n");
feidigui(root);
printf("\n");
printf("%d\n", getHeight(root));
return 0;
}
```