使用c语言单向链表实现简单学生成绩管理系统

本文优化整个代码框架结构，完善用户可以对系统信息的修改。本例中，使用一系列c语言知识，有利于巩固c语言语法，具体包括结构体，枚举，while循环，switch语句，还有数据结构等内容。

基于上一个内容（使用c语言单向链表实现简单学生成绩管理系统（1））作如下修改。
修改1：实现基于姓名对数据进行修改和删除

简单解释下节点的删除

代码实现

//链表中删除数据--根据姓名
int delete_data(student_msg_t * head,char * name)
{if(isnull(head)){printf("no student msg\n");return -1;}int flag = 0;student_msg_t * temp_node;//用于备份要删除的节点地址temp_node = (student_msg_t*)malloc(sizeof(student_msg_t));if(temp_node == NULL){printf("create temp node fail\n");return -1;}while(head->next != NULL){if(0 == strncmp(head->next->msg.name,name,strlen(name))){//删除此节点temp_node = head->next;head->next = temp_node->next;free(temp_node);temp_node = NULL;flag = 1; //判断找到需要删除的信息break;}elsehead = head->next;}if(flag == 0)printf("the list do not have the name\n");elseprintf("delete the name msg is success\n");return 0;
}//链表中修改数据--根据姓名
int modify_data(student_msg_t * head,grade_msg_t * grade_msg)
{if(isnull(head)){printf("no student msg\n");return -1;}int flag = 0;while(head->next != NULL){if(0 == strncmp(head->next->msg.name,grade_msg->name,strlen(grade_msg->name))){//修改此节点head->next->msg.chinese = grade_msg->chinese;head->next->msg.math = grade_msg->math;head->next->msg.english = grade_msg->english;flag = 1; //判断找到需要删除的信息break;}else{head = head->next;}}if(flag == 0)printf("the list do not have the name\n");elseprintf("modify msg success\n");return 0;
}

修改2：通过输入控制，选择对数据的操作类型
下面贴上完整的代码

#include<stdio.h>
#include<stdlib.h>
#include<string.h>//个人信息结构体,各科成绩可自定义添加
typedef struct grade_msg
{char name[16];char sex;int chinese;int math;int english;}grade_msg_t;//链表结构体
typedef struct student_msg
{grade_msg_t msg;struct student_msg * next;
}student_msg_t;//定义操作类型枚举
enum operate_type
{INSERT_TYPE = 1,DELETE_TYPE,PRINTF_TYPE,MODIFY_TYPE
};//创建链表头
student_msg_t * create_slist_head()
{student_msg_t * head;//申请空间head = (student_msg_t *)malloc(sizeof(student_msg_t));if(head == NULL){printf("create slist head fail\n");return NULL;}//初始化head->next = NULL;return head;
}//判断链表中有无数据
//返回1为空，0为非空
int isnull(student_msg_t *  head)
{if(head->next == NULL)return 1;elsereturn 0;
}//链表头添加数据
int insert_data(student_msg_t * head,grade_msg_t * msg)
{printf("enter insert msg\n");student_msg_t * new_node;new_node = (student_msg_t * )malloc(sizeof(student_msg_t));if(new_node == NULL){printf("insert,create space fail\n");return -1;}strcpy(new_node->msg.name,msg->name);new_node->msg.sex = msg->sex;new_node->msg.chinese = msg->chinese;new_node->msg.math = msg->math;new_node->msg.english = msg->english;new_node->next = head->next;head->next = new_node;return 0;
}//打印所有信息
int printf_list(student_msg_t *  head)
{if(isnull(head)){printf("no student msg\n");return -1;}while(head->next != NULL){head = head->next;printf("name:%s,sex:%c,chinese:%d,math:%d,english:%d\n",head->msg.name,head->msg.sex,head->msg.chinese,head->msg.math,head->msg.english);}return 0;}//链表中删除数据--根据姓名
int delete_data(student_msg_t * head,char * name)
{if(isnull(head)){printf("no student msg\n");return -1;}int flag = 0;student_msg_t * temp_node;temp_node = (student_msg_t*)malloc(sizeof(student_msg_t));if(temp_node == NULL){printf("create temp node fail\n");return -1;}while(head->next != NULL){if(0 == strncmp(head->next->msg.name,name,strlen(name))){//删除此节点temp_node = head->next;head->next = temp_node->next;free(temp_node);temp_node = NULL;flag = 1; //判断找到需要删除的信息break;}elsehead = head->next;}if(flag == 0)printf("the list do not have the name\n");elseprintf("delete the name msg is success\n");return 0;
}//链表中修改数据--根据姓名
int modify_data(student_msg_t * head,grade_msg_t * grade_msg)
{if(isnull(head)){printf("no student msg\n");return -1;}int flag = 0;while(head->next != NULL){if(0 == strncmp(head->next->msg.name,grade_msg->name,strlen(grade_msg->name))){//修改此节点head->next->msg.chinese = grade_msg->chinese;head->next->msg.math = grade_msg->math;head->next->msg.english = grade_msg->english;flag = 1; //判断找到需要删除的信息break;}else{head = head->next;}}if(flag == 0)printf("the list do not have the name\n");elseprintf("modify msg success\n");return 0;
}int main(int argc, const char *argv[])
{student_msg_t * msg_head;char msg_str[64];char name_str[16];int flag;grade_msg_t insert_msg;msg_head = create_slist_head();if(msg_head == NULL){printf("create student msg head fail\n ");return -1;}while(1){printf("input operate flag \n");printf("1 INSERT_TYPE\n");printf("2 DELETE_TYPE\n");printf("3 PRINTF_TYPE\n");printf("4 MODIFY_TYPE\n");scanf("%d",&flag);getchar();switch(flag){case INSERT_TYPE:{//姓名 字符串 性别 字符类型 语数英 整型printf("please input 姓名[enter] 性别[enter] 语文[enter] 数学[enter] 英语[enter]\n");//简化信息输入printf("------------input start------------\n");scanf("%s",insert_msg.name);getchar();scanf("%c",&insert_msg.sex);getchar();scanf("%d",&insert_msg.chinese);getchar();scanf("%d",&insert_msg.math);getchar();scanf("%d",&insert_msg.english);getchar();printf("------------input end------------\n");//插入数据insert_data(msg_head,&insert_msg);}break;case PRINTF_TYPE:{printf("==========printf start==========\n");if(msg_head -> next != NULL)printf_list(msg_head);printf("==========printf end=========\n");}break;case DELETE_TYPE:{printf("<delete>please enter delete name\n");memset(name_str,0,sizeof(name_str));scanf("%s",name_str);getchar();delete_data(msg_head,name_str);}break;case MODIFY_TYPE:{printf("<modify>please input modify name\n");memset(name_str,0,sizeof(insert_msg.name));scanf("%s",insert_msg.name);getchar();scanf("%d",&insert_msg.chinese);getchar();scanf("%d",&insert_msg.math);getchar();scanf("%d",&insert_msg.english);getchar();modify_data(msg_head,&insert_msg);}break;default:printf("no have the operate type\n");}}return 0;
}

本例是笔者闲暇之余顺手写个一个简单实例（此功能使用sqlite3数据库实现更为简单，有时间再实现），主要是为了巩固下c语言的基本知识点，复习下单向链表，后面还有最后一篇结尾，在程序中加入io操作，保存备份信息到文件，并且可以使程序退出，重新运行可直接载入信息。