嵌入式学习——C语言基础——day15

1. 段错误调试

1.1 打印法

        在可能出现错误的位置加入打印,前一句能够打印出来,后一句打印不出来,问题就可以定位到两次打印中间的代码

1.2 gbd调试法

        1. 编译代码时加入-g选项

             gcc filename.c -g

        2. 使用gdb调试生成的代码

             gdb a.out

        3. gdb调试命令

                l                   查看代码
                b 函数名/行号        设置断点
                r                   运行代码
                n                   单步运行
                c                   直接运行到下一处断点
                s                   进入函数内部调试
                p   变量名          查看变量对应的值
                q                   退出

1.3 core文件调试方法

        1. 配置core文件

ubuntu 产生core文件-CSDN博客文章浏览阅读251次。ubuntu 产生core文件https://blog.csdn.net/weixin_43847267/article/details/130546569?ops_request_misc=%257B%2522request%255Fid%2522%253A%2522169243011316800225536999%2522%252C%2522scm%2522%253A%252220140713.130102334.pc%255Fall.%2522%257D&request_id=169243011316800225536999&biz_id=0&utm_medium=distribute.pc_search_result.none-task-blog-2~all~first_rank_ecpm_v1~rank_v31_ecpm-2-130546569-null-null.142%5Ev93%5EchatgptT3_2&utm_term=Ubuntu%E4%BA%A7%E7%94%9Fcore%E6%96%87%E4%BB%B6&spm=1018.2226.3001.4187        2. ulimit -c unlimited

        3. 编译代码加入-g选项

        4. 运行代码使其产生段错误,段错误产生后会生成一个包含错误信息的core文件

        5. gdb a.out core 找到错误产生的位置

        注意：打印法和gdb法可以调试任意错误，但core文件调试法只能调试段错误

2. 链表以及链表的增删改查

2.1 创建空链表

typedef struct node 
{
	int data;
	struct node *pnext;
}linknode;

linknode *createlinklist(void)
{
	linknode *ptmpnode = NULL;

	ptmpnode = malloc(sizeof(linknode));
	if (NULL == ptmpnode)
	{
		printf("malloc failed!\n");
		return NULL;
	}

	ptmpnode->pnext = NULL;

	return ptmpnode;
}

2.2 头插法

int insertheadlinklist(linknode *phead, int tmpdata)
{
	linknode *ptmpnode = NULL;

	ptmpnode = malloc(sizeof(linknode));
	if (NULL == ptmpnode)
	{
		printf("malloc failed!\n");
		return -1;
	}

	ptmpnode->data = tmpdata;
	ptmpnode->pnext = phead->pnext;
	phead->pnext = ptmpnode;

	return 0;
}

2.3  打印链表信息

int showlinklist(linknode *phead)
{
	linknode *ptmp = NULL;

	ptmp = phead->pnext;
	while (ptmp != NULL)
	{
		printf("%d ", ptmp->data);
		ptmp = ptmp->pnext;
	}
	printf("\n");

	return 0;
}

2.4 寻找链表中的元素

linknode *findlinklist(linknode *phead, int tmpdata)
{
	linknode *ptmpnode = NULL;

	ptmpnode = phead->pnext;
	while (ptmpnode != NULL)
	{
		if (ptmpnode->data == tmpdata)
		{
			return ptmpnode;
		}
		ptmpnode = ptmpnode->pnext;
	}
	
	return NULL;
}

2.5 链表元素的替换

int replacelinklist(linknode *phead, int oldata, int newdata)
{
	linknode *ptmpnode = NULL;

	ptmpnode = phead->pnext;
	while (ptmpnode != NULL)
	{
		if (ptmpnode->data == oldata)
		{
			ptmpnode->data = newdata;
		}
		ptmpnode = ptmpnode->pnext;
	}

	

2.6 头插法

int insertheadlinklist(linknode *phead, int tmpdata)
{
	linknode *ptmpnode = NULL;

	ptmpnode = malloc(sizeof(linknode));
	if (NULL == ptmpnode)
	{
		printf("malloc failed!\n");
		return -1;
	}

	ptmpnode->data = tmpdata;
	ptmpnode->pnext = phead->pnext;
	phead->pnext = ptmpnode;

	return 0;
}

2.7 尾插法

int inserttaillinklist(linknode *phead, int tmpdata)
{
	linknode *ptmpnode = NULL;
	linknode *plastnode = NULL;

	ptmpnode = malloc(sizeof(linknode));
	if (NULL == ptmpnode)
	{
		printf("malloc failed!\n");
		return -1;
	}

	ptmpnode->data = tmpdata;
	ptmpnode->pnext = NULL;

	plastnode = phead;
	while (plastnode->pnext != NULL)
	{
		plastnode = plastnode->pnext;
	}
	plastnode->pnext = ptmpnode;

	return 0;
}

2.8 链表的删除

int deletelinklist(linknode *phead, int tmpdata)
{
	linknode *ptmpnode = NULL;
	linknode *pprenode = NULL;

	pprenode = phead;
	ptmpnode = phead->pnext;

	while (ptmpnode != NULL)
	{
		if (ptmpnode->data == tmpdata)
		{
			pprenode->pnext = ptmpnode->pnext;
			free(ptmpnode);
			ptmpnode = pprenode->pnext;
		}
		else 
		{
			ptmpnode = ptmpnode->pnext;
			pprenode = pprenode->pnext;
		}
	}

	return 0;
}

2.9 链表的摧毁和回收

int destroylinklist(linknode **pphead)
{
	linknode *ptmpnode = NULL;
	linknode *pfreenode = NULL;

	ptmpnode = pfreenode = *pphead;
	while (ptmpnode != NULL)
	{
		ptmpnode = ptmpnode->pnext;
		free(pfreenode);
		pfreenode = ptmpnode;
	}
	*pphead = NULL;

	return 0;
}

2.10 链表的冒泡排序法

int bubblesortlinklist(linknode *phead)
{
	linknode *ptmpnode1 = NULL;
	linknode *ptmpnode2 = NULL;
	linknode *pend = NULL;
	int tmp = 0;

	while (1)
	{
		ptmpnode1 = phead->pnext;
		ptmpnode2 = phead->pnext->pnext;
		
		if (ptmpnode2 == pend)
		{
			break;
		}

		while (ptmpnode2 != pend)
		{
			if (ptmpnode1->data > ptmpnode2->data)
			{
				tmp = ptmpnode1->data;
				ptmpnode1->data = ptmpnode2->data;
				ptmpnode2->data = tmp;
			}

			ptmpnode1 = ptmpnode1->pnext;
			ptmpnode2 = ptmpnode2->pnext;
		}

		pend = ptmpnode1;
	}
	return 0;
}

2.11 链表的选择排序法

int selectsortlinklist(linknode *phead)
{
	linknode *pselectnode = NULL;
	linknode *pminnode = NULL;
	linknode *ptmpnode = NULL;
	int tmp;
	
	pselectnode = phead->pnext;
	while (pselectnode->pnext != NULL)
	{
		pminnode = pselectnode;
		ptmpnode = pselectnode->pnext;
		while (ptmpnode != NULL)
		{
			if (ptmpnode->data < pminnode->data)
			{
				pminnode = ptmpnode;
			}

			ptmpnode = ptmpnode->pnext;
		}
		if (pminnode != pselectnode)
		{
			tmp = pminnode->data;
			pminnode->data = pselectnode->data;
			pselectnode->data = tmp;
		}

		pselectnode = pselectnode->pnext;
	}

	return 0;
}