再“C”一点

已于 2024-04-09 09:40:16 修改
阅读量421 收藏 10
点赞数 9
文章标签： c语言 开发语言
于 2024-01-11 18:42:44 首次发布
版权声明：本文为博主原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接和本声明。
本文链接：https://blog.youkuaiyun.com/weixin_70940338/article/details/135536505
版权

文章目录

再“C”一点

MY BLOG: 优快云

链表

静态链表的创建

#include <stdio.h>

struct Text
{
	int data;
	struct Text *pNext;
};

struct Text *head=NULL;
struct Text t1={1,NULL};
struct Text t2={2,NULL};
struct Text t3={3,NULL};
struct Text t4={4,NULL};

int main()
{
    head=&t1;
	t1.pNext=&t2;
	t2.pNext=&t3;
	t3.pNext=&t4;

	return 0;
}

打印链表数据

函数：

void printLink(struct Text *p)
{
	while(p!=NULL)
	{
		printf("%d ",p->data);
		p=p->pNext;
	}
	putchar('\n');
}

调用：

printLink(&t1);

从指定结点后方插入新结点

函数：

int insertFromBehind(struct Text *p,int data,struct Text *newdata)
{
	while(p!=NULL)
	{
		if(p->data==data)
		{
			newdata->pNext=p->pNext;
			p->pNext=newdata;
			return 1;
		}
		p=p->pNext;
	}
	printf("Not Found %d!\n",data);

	return 0;
}

调用：

struct Text t5={5,NULL};
insertFromBehind(&t1,2,&t5);

从指定结点前方插入新结点

函数：

struct Text* insertFromBefor(struct Text *head,int data,struct Text *newdata)
{
	struct Text *p=head;
	if(data==p->data)
	{
		newdata->pNext=p;
		return newdata;
	}
	while(p->pNext!=NULL)
	{
		if(p->pNext->data==data)
		{
			newdata->pNext=p->pNext;
			p->pNext=newdata;
			printf("success insert %d before %d!\n",p->pNext->data,data);
			//printf("success insert %d before %d!\n",newdata->data,data);
			return head;
		}
		p=p->pNext;
	}
	printf("Not find %d in the chain!\n",data);
	return head;
}

调用

struct Text t6={6,NULL};
insertFromBefor(&t1,3,&t6);

总结1

#include <stdio.h>

struct Text
{
	int data;
	struct Text *pNext;
};

struct Text *head=NULL;
struct Text t1={1,NULL};
struct Text t2={2,NULL};
struct Text t3={3,NULL};
struct Text t4={4,NULL};

struct Text t5={5,NULL};
struct Text t6={6,NULL};

void printLink(struct Text *p);
int insertFromBehind(struct Text *p,int date,struct Text *newdata);
struct Text* insertFromBefor(struct Text *head,int data,struct Text *newdata);

int main()
{
    head=&t1;
	t1.pNext=&t2;
	t2.pNext=&t3;
	t3.pNext=&t4;
	
	printLink(&t1);
	insertFromBehind(&t1,2,&t5);
	printLink(&t1);
	insertFromBefor(&t1,5,&t6);
	printLink(&t1);
	
	return 0;
}

void printLink(struct Text *p)
{
	while(p!=NULL)
	{
		printf("%d ",p->data);
		p=p->pNext;
	}
	putchar('\n');
}

int insertFromBehind(struct Text *p,int data,struct Text *newdata)
{
	while(p!=NULL)
	{
		if(p->data==data)
		{
			newdata->pNext=p->pNext;
			p->pNext=newdata;
			return 1;
		}
		p=p->pNext;
	}
	printf("Not Found %d!\n",data);

	return 0;
}

struct Text* insertFromBefor(struct Text *head,int data,struct Text *newdata)
{
	struct Text *p=head;
	if(data==p->data)
	{
		newdata->pNext=p;
		return newdata;
	}
	while(p->pNext!=NULL)
	{
		if(p->pNext->data==data)
		{
			newdata->pNext=p->pNext;
			p->pNext=newdata;
			printf("success insert %d before %d!\n",p->pNext->data,data);
			//printf("success insert %d before %d!\n",newdata->data,data);
			return head;
		}
		p=p->pNext;
	}
	printf("Not find %d in the chain!\n",data);
	return head;
}

动态链表的创建

头插法

struct Text* headInsert(struct Text *head,struct Text *new)
{
	if(head==NULL)  //若传入链表头结点为NULL（链表为空）
	{
		return new;
	}
	else
	{
		new->pNext=head;
		head=new;
		return head;
	}
}

尾插法

struct Text* tailInsert(struct Text *head,struct Text *new)
{
	if(head==NULL)  //若传入链表头结点为NULL（链表为空）
	{
		return new;
	}
	else
	{
		struct Text *p=head;
		while(p-pNext!=NULL)
		{
			p=p->pNext;     //往后找，直至链尾
		}
		p->pNext=new;
		return new;
		new->pNext=head;
		head=new;
		return head;
	}
}

创建结点

函数：

struct Node* createNode(int data)
{
    struct Node *newNode=(struct Node*)malloc(sizeof(struct Node));
    newNode->date=data;
    newNode->next=NULL;
    return newNode;
}

调用：

int main()
{   
	struct Text *newNode=createNode(3);
	printLink(newNode);

	return 0;
}

删除结点

struct Text* delNode(struct Text* head,int data)
{
	struct Text *p=head;
	if(p->data==data)
	{
		head=p->pNext;
		free(p); //释放原头节点内存
		return head;
	}
	while(p->pNext!=NULL)
	{
		if(p->pNext->data==data)
		{			
			p->pNext=p->pNext->pNext;
			struct Text *del_p=p->pNext;
			free(del_p);  //释放删除掉的结点的内存
			return head;
		}
		p=p->pNext;
	}
	printf("Failed del %d\n",data);
	
	return head;
}

总结2

#include <stdio.h>
#include <stdlib.h>

struct Text
{
	int data;
	struct Text *pNext;
};

void printLink(struct Text *p);
struct Text* createNode(int data);
int insertFromBehind(struct Text *p,int data,struct Text *newdata);
struct Text* insertFromBefore(struct Text *p,int data,struct Text *newdata);
struct Text* delNode(struct Text* head,int data);
struct Text* headInsert(struct Text *head,struct Text *new);
struct Text* tailInsert(struct Text *head,struct Text *new);

int main()
{   
	struct Text *newNode=createNode(3); //动态创建结点
	printLink(newNode);   //打印当前链表
	//newNode=delNode(newNode,1); //尝试删除结点
	//printLink(newNode);
	//newNode=delNode(newNode,3);  //删除数据为3的结点
	//printLink(newNode);
	//struct Text *newNode2=createNode(5);
	//insertFromBehind(newNode,3,newNode2);
	//printLink(newNode);
	//struct Text *newNode3=createNode(6);
	//newNode=insertFromBefore(newNode,3,newNode3);
	//printLink(newNode);  
	
	struct Text *newNode4=malloc(sizeof(struct Text));
	newNode=headInsert(newNode,newNode4);
	printLink(newNode);
	struct Text *newNode5=malloc(sizeof(struct Text));
	newNode=tailInsert(newNode,newNode5);
	printLink(newNode);
	//newNode=headInsert(newNode,newNode3);
	//printLink(newNode);
	
	free(newNode); //释放链表内存
	newNode=NULL;  //指向NULL
    printLink(newNode);

	return 0;
}

void printLink(struct Text *p)
{
	while(p!=NULL)
	{
		printf("%d ",p->data);
		p=p->pNext;
	}
	putchar('\n');
}

int insertFromBehind(struct Text *p,int data,struct Text *newdata)
{
	while(p!=NULL)
	{
		if(p->data==data)
		{
			newdata->pNext=p->pNext;
			p->pNext=newdata;
			return 1;
		}
		p=p->pNext;
	}
	printf("Not Found %d!\n",data);

	return 0;
}

struct Text* insertFromBefore(struct Text *head,int data,struct Text *newdata)
{
	struct Text *p=head;
	if(data==p->data)
	{
		newdata->pNext=p;
		return newdata;
	}
	while(p->pNext!=NULL)
	{
		if(p->pNext->data==data)
		{
			newdata->pNext=p->pNext;
			p->pNext=newdata;
			printf("success insert %d before %d!\n",p->pNext->data,data);
			//printf("success insert %d before %d!\n",newdata->data,data);
			return head;
		}
		p=p->pNext;
	}
	printf("Not find %d in the chain!\n",data);
	return head;
}

struct Text* createNode(int data)
{
    struct Text *newNode=(struct Text*)malloc(sizeof(struct Text));
	if (newNode == NULL)
    {
        fprintf(stderr, "Memory allocation failed\n");
        exit(EXIT_FAILURE);
    }
    newNode->data=data;
    newNode->pNext=NULL;
    return newNode;
}

struct Text* delNode(struct Text* head,int data)
{
	struct Text *p=head;
	if(p->data==data)
	{
		head=p->pNext;
		free(p); //释放原头节点内存
		return head;
	}
	while(p->pNext!=NULL)
	{
		if(p->pNext->data==data)
		{			
			p->pNext=p->pNext->pNext;
			struct Text *del_p=p->pNext;
			free(del_p);  //释放删除掉的结点的内存
			return head;
		}
		p=p->pNext;
	}
	printf("Failed del %d\n",data);
	
	return head;
}

struct Text* headInsert(struct Text *head,struct Text *new)
{
	if(head==NULL)  //若传入链表头结点为NULL（链表为空）
	{
		return new;
	}
	else
	{
		new->pNext=head;
		head=new;
		return head;
	}
}

struct Text* tailInsert(struct Text *head,struct Text *new)
{
	if(head==NULL)  //若传入链表头结点为NULL（链表为空）
	{
		return new;
	}
	else
	{
		struct Text *p=head;
		while(p->pNext!=NULL)
		{
			p=p->pNext;     //往后找，直至链尾
		}
		p->pNext=new;
		return head;
	}
}

结合函数指针动态创建链表

#include <stdio.h>
#include <stdlib.h>

typedef struct Text
{
	int data;
	struct Text *pNext;
}text;

void printLink(struct Text *p);
struct Text* headInsert(struct Text *head,struct Text *newNode);
struct Text* tailInsert(struct Text *head,struct Text *newNode);
struct Text* activeCreatNode(struct Text *head,struct Text *(*func)(struct Text *head,struct Text *newNode));

int main()
{
    text *head=NULL;
    text newdata={2,NULL};
    printLink(head);
    
    head=activeCreatNode(head,tailInsert);
    printLink(head);
    head=activeCreatNode(head,headInsert);
    printLink(head);
    return 0;
}

void printLink(struct Text *p)
{
	while(p!=NULL)
	{
		printf("%d ",p->data);
		p=p->pNext;
	}
	putchar('\n');
}

struct Text* headInsert(struct Text *head,struct Text *newNode)
{
	if(head==NULL)  //若传入链表头结点为NULL（链表为空）
	{
		return newNode;
	}
	else
	{
		newNode->pNext=head;
		head=newNode;
		return head;
	}
}

struct Text* tailInsert(struct Text *head,struct Text *newNode)
{
	if(head==NULL)  //若传入链表头结点为NULL（链表为空）
	{
		return newNode;
	}
	else
	{
		struct Text *p=head;
		while(p->pNext!=NULL)
		{
			p=p->pNext;     //往后找，直至链尾
		}
		p->pNext=newNode;
		return head;
	}
}

struct Text* activeCreatNode(struct Text *head,struct Text *(*func)(struct Text *head,struct Text *newNode))
{
    while(1)
    {
        struct Text *newNode=(struct Text*)malloc(sizeof(struct Text));
        printf("Please input newdata:");
        scanf("%d",&(newNode->data));
        if(newNode->data==0)
        {
         	free(newNode);
            printf("end input\n");
            return head;
		}
        head=(*func)(head,newNode);
	}
}

函数指针

调用方式

#include <stdio.h>

void PrintWelcom(void)
{
    printf("哈喽，welcome\n");
}

int main()
{
    PrintWelcom(); //直接调用函数

    void (*func)(void)=PrintWelcom; //定义一个函数指针来调用
    (*func)();

    return 0; 
}

实际案例

#include <stdio.h>
#include <stdlib.h>

int GetMax(int a,int b)
{
    return a>b?a:b;
}

int GetMin(int a,int b)
{
    return a<b?a:b;
}

int GetSum(int a,int b)
{
    return a+b;
}

int dataHandler(int a,int b,int (*pfunc)(int a,int b))
{
    int data;
    data=(*pfunc)(a,b);
}

int main()
{
    int a=10;
    int b=-20;
    int cmd;
    int ret;
    // int (*pfunc)(int a,int b);
    int (*pfunc)(int,int); //省略形参的名字

    printf("请输入一个数字.1:取最大值、2:取最小值、3:取两数之和\n");
    scanf("%d",&cmd);

    switch(cmd)
    {
        case 1:
            printf("最大值为:");
            pfunc=GetMax;
            break;
        case 2:
            printf("最小值为:");
            pfunc=GetMin;
            break;
        case 3:
            printf("和为:");
            pfunc=GetSum;
            break;
        default:
            printf("输入错误");
            exit(-1);
    }
    ret=dataHandler(a,b,pfunc);
    printf("ret=%d\n",ret);

    return 0; 
}

文件操作基础

打开和关闭文件

定义文件指针

FILE *fp;

打开文件fopen()

"r":只读，文件必须存在，光标位于文件开头

"w":只写，如果文件不存在则创建，如果文件存在则截断，光标位于文件开头

"a":追加，如果文件不存在则创建，光标位于文件末尾

"r+"、"w+"、"a+"：读写，文件必须存在

fp=fopne("test.txt","r"); //双引号
if(fp==NULL)
    printf("文件打开失败\n");

关闭文件fclose()

fclose(fp);

测试

#include <stdio.h>

int main()
{
    FILE *fp;
    
    fp=fopen("test.c","r");
    if(fp==NULL)
        printf("Open failed!\n");
    else
        printf("Open succeed!\n");
    fclose(fp);
    
    return 0;
}

读取文件内容

测试fgetc()（fread()）

#include <stdio.h>

int main()
{
    FILE *fp;
    
    fp=fopen("test.c","r");
    if(fp==NULL)
        printf("Open failed!\n");
    else
        printf("Open succeed!\n");
    
    char c;
    while((c=fgetc(fp))!=EOF)
    {
        printf("%c",c);
    }
    
    fclose(fp);
    
    return 0;
}

写入文件内容

测试fprintf()（fwrite()）

#include <stdio.h>

int main()
{
    FILE *fp;
    
    fp=fopen("filetest.txt","w"); 
    if(fp==NULL)
        printf("Open failed!\n");
    else
        printf("Open succeed!\n");
    
    fprintf(fp,"Hello");
    
    char c;
    while((c=fgetc(fp))!=EOF)
        printf("%c",c);
    printf("\n",c);
    fclose(fp);
    
    return 0;
}

光标定位

测试：移动光标fseek(),获取光标位置ftell()

#include <stdio.h>
#include <stdlib.h>

int main()
{
    FILE *fp;
    
    fp=fopen("filetest.txt","w+"); 
    if(fp==NULL)
    {
        printf("Open failed!\n");
        exit(-1);
    }
    else
    {
        printf("Open succeed!\n");
	}

    fprintf(fp,"Hello,World!");
    
    /*偏移量0:光标相对于起始位置的偏移量
    **起始位置SEEK_END：文件末尾
    **       SEEK_SET: 文件开头
    **       SEEK_CUR: 当前位置
    */
    fseek(fp,6,SEEK_SET);
    char c;
    while((c=fgetc(fp))!=EOF)
        printf("%c",c);
    putchar('\n');
    
    printf("光标位置：%ld\n",ftell(fp));
    fclose(fp);
    
    return 0;
}

微信公众号

关注博主微信公众号：灵萧宝殿
分享更多有趣有料内容
点此扫码

评论
添加红包

请填写红包祝福语或标题

个

红包个数最小为10个

元

红包金额最低5元

当前余额3.43元 前往充值 >
需支付：10.00元
成就一亿技术人!
领取后你会自动成为博主和红包主的粉丝 规则
hope_wisdom
发出的红包
实付元
使用余额支付
点击重新获取
扫码支付
钱包余额 0

抵扣说明：

1.余额是钱包充值的虚拟货币，按照1:1的比例进行支付金额的抵扣。
2.余额无法直接购买下载，可以购买VIP、付费专栏及课程。

余额充值