C语言小程序-基于链表的简易学生信息管理

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程序支持增加、查询、删除、存盘和读取操作

一程序定义和函数声明

　　头文件studentsys.h定义如下

/*  student management system by list  */
#ifndef _StudentSys_H
#define _StudentSys_H

#define MAX 25       /* lenth of name string */   
typedef struct _Grade Grade;;
typedef struct StdNode Std;;
typedef struct ListNode *List;

　　全局结构体定义

/* 6 courses */
struct _Grade{
    int Chinese;
    int Math;
    int English;
    int Programming;
    int Physic;
    int Geology; 
};

/*  student info */    
struct StdNode {
    int Id;        /* student id */
    char name[MAX];/* student name */
    Grade grades;  /* student grades */
};

struct ListNode {
    Std info;
    List next;
};

　　函数声明

　　/* 1->Add 　　2->Find 　　3->Del 　　4->Brows 　　5->Store
　　6->Read 　 7->DelAll　 8->Cls 　　 9->Quit */ 功能选择键

int AddStd( List L, int Id, char *name, Grade grades );
/* flag:0 by id, 1 by name */
int FindStd(List L, int flag, int Id ,char *name); 
int DeleteStd( List L, int Id );
void PrintInfo( List L );
void PrintAll( List L );
int StoreInfo( List L );
List ReadInfo( );
void DestoryInfo( List L ); 
int IsRepeat( List L, int Id );
void selectInfo();

二源文件studentsys.c

　　主体部分，由while循环下的switch分支进行功能选择

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "studentsys.h"

int main(void)
{
    List L; /* Head Node */
    L = (List)malloc(sizeof( struct ListNode ));
    L->next = NULL;
    
    int i, flag;  /*  flag做为查找方式标志， 0由Id, 1由姓名进行搜索  */
    int option, Id = 0; /* option选择功能， init info */
    char name[MAX]= "   ";
    Grade grades;

    printf("                       Starting                       \n");
    printf("          Student Management system, ver:0.101 \n");  
    printf("******************************************************\n");
    printf("                    学生管理系统\n");
    printf("$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$\n");
    selectInfo();
    while ( 1 ) {
        scanf("%d", &option);
        switch ( option ) {
            case 1: printf("Please in put id, name, six grades:\n");
                    scanf("%d %s", &Id, name);
                    scanf("%d %d %d %d %d %d", &grades.Chinese, &grades.Math,
                         &grades.English, &grades.Programming,&grades.Physic, 
                         &grades.Geology );
                    if ( AddStd( L, Id, name, grades ) == 1 ) {
                        printf("Added student.\n");
                    } else {
                        printf("Sorry, can't add student\n");
                    }
                    break;
                    
            case 2: printf("select method: 0 by Id, 1 by name\n");
                    scanf("%d", &flag);
                    printf("Please in put id, name\n");
                    scanf("%d %s", &Id, name); /* notice & */
                    if ( FindStd( L, flag, Id, name ) == 1 ) {
                        printf("found student\n");
                    } else {
                        printf("sorry, can't found student\n");
                    }
                    break;
                    
            case 3: printf("Which id you want to del: ");
                    scanf("%d", &Id);
                    if ( DeleteStd( L, Id ) ) {
                        printf("Successfully Delete!\n");
                    } else {
                        printf(" Not found!\n");
                    }
                    break;        
                                
            case 4: PrintAll( L ); 
                    break;    
                    
            case 5: if ( StoreInfo( L ) ) {
                            printf("Write successfulluy!\n");
                    } else {
                        printf("Failed to read!\n");
                    } 
                    break;    
                    
            case 6: L = ReadInfo( ); 
                    break;                
            case 7: DestoryInfo( L ); 
                    break;
            case 8: system("cls");
                    selectInfo();
                    break;
            case 9: exit(0); 
                    break;
            default: printf("error!请重新输入!\n");
        }
    }
    return 0;    
}

　　函数主体，由简单的链表的插入、删除和遍历

int AddStd( List L, int Id, char *name, Grade grades ) 
{
    List Head = L;
    List Cur;
    if( IsRepeat( L, Id) == 1 ) {
        printf(" Id repeat!!!\n");
        return 0;
    }
    /*  链表的插入 */
    Cur = (List)malloc(sizeof( struct ListNode ));
    if ( Cur != NULL ) {
        Cur->info.Id = Id;
        strcpy( Cur->info.name, name);
        Cur->info.grades.Chinese = grades.Chinese;
        Cur->info.grades.Math = grades.Math;
        Cur->info.grades.English = grades.English;
        Cur->info.grades.Programming = grades.Programming;
        Cur->info.grades.Physic = grades.Physic;
        Cur->info.grades.Geology = grades.Geology;                    
        
        Cur->next = Head->next;
        Head->next = Cur;
        
        return 1;
    } else {
        printf("Failed to malloc!\n");    
        return 0;
    }
}

int FindStd( List L, int flag, int Id , char *name )
{ 
    List Cur = L->next;
    while ( Cur != NULL ) {
        if( flag == 1 ) {
            if ( strcmp( name, Cur->info.name ) == 0 ) {
                PrintInfo(Cur);
                break;
            }
        } else if ( flag == 0 ) {
            if ( Cur->info.Id == Id ) {
                PrintInfo(Cur);
                break;
            }
        }
        Cur = Cur->next;    
    }
    if ( Cur == NULL ){
        return 0;
    } else {
        return 1;
    } 
}

int DeleteStd( List L, int Id )
{
    List Pre = L;
    List Cur = Pre->next;
    
    if( L->next == NULL ) {
        printf("Empty Node!\n");
        return 0;
    } else {
        while ( Cur != NULL ) {
            if ( Cur->info.Id == Id ) {  
                 /* 找到对应编号 */
                Pre->next = Cur->next;
                free(Cur);
                break;
            } 
            Pre = Cur;
            Cur = Cur->next; 
        }
        if ( Cur == NULL ) {
            return 0; 
        } else {
            return 1;
        }
    } /* 1 else */    
}

void PrintInfo( List L )
{
    List Cur = L;
    if ( Cur != NULL ) {
        printf("ID: %d  ", Cur->info.Id);
        printf("Name: %s\n", Cur->info.name);
        printf("Chinese    :%d   ", Cur->info.grades.Chinese);
        printf("Math       :%d   ", Cur->info.grades.Math);
        printf("English    :%d\n", Cur->info.grades.English);
        printf("Programming:%d   ", Cur->info.grades.Programming);
        printf("Physic     :%d   ", Cur->info.grades.Physic);
        printf("Geology    :%d\n", Cur->info.grades.Geology);
    } 
}

void PrintAll( List L )
{
    List Cur = L->next;
    int i = 0;
    while ( Cur != NULL ) {
        i++;
        printf("%d-->Student ", i);
        PrintInfo( Cur );    
        Cur = Cur->next;
    }
}
void DestoryInfo( List L )
{
    List Cur, Tmp;
    Cur = L->next;
    while ( Cur    != NULL ) {
        Tmp = Cur->next;
        free( Cur );
        Cur = Tmp;
    }
    L->next = NULL;
     printf("删除所有学生信息成功!\n");
}

int IsRepeat( List L, int Id )
{
    List Cur = L->next;
    int flag = 0;
    while ( Cur != NULL ) {
        if ( Cur->info.Id == Id ) {
　　　　　　　flag = 1；
　　　　　　　break;　　　　
　　　　　}      
　　　　 Cur = Cur->next;  
    }
　　return flag;
}

void selectInfo()
{
    printf("Stumansys 请选择：\n");
    printf("(1)---增加学生 (2)---查询学生 (3)---删除学生 \n");
    printf("(4)---查看全部 (5)---记录存盘 (6)---读取信息\n");
    printf("(7)---删除所有 (8)---清除屏幕 (9)---退出系统\n");    
}

　　文件读写操作

　　　　1. 链表写入文件，每次写一个结构体，直到链表尾。

　　　　2. 文件读取，使用feof(fp)函数判断是否达到文件流尾，否则读取一个结构体，并尾插入链表。

int StoreInfo( List L )
{
    FILE *fp = fopen("student.data", "w");
    List H = L->next;
    const int size = 1;
    int ret = -1; /* default */
    
    if ( fp == NULL ) {
        printf("Failed to open file!\n");
    } else if( H == NULL ) {
        printf("Empty student info!\n");
    } else {        
        /* write list into fp */
        while ( H != NULL ) {
            ret = fwrite( H, sizeof(H->info), size, fp );
            H = H->next;    
        }
        ret = 1;
    }
    fclose( fp );
    return ret;
}

List ReadInfo( )
{
    int i = 0; /* count */
    List L, P, tmp;
    P = L = (List)malloc( sizeof(struct ListNode) );
    FILE *fp = fopen("student.data", "r");
    
    if ( fp == NULL ) {
        printf("Failed to read file!\n");
        return NULL;
    } 
    /* 假如文件为空,检查文件结束符 feof在到达文件流尾返回非零值 */
     if ( feof(fp) != 0 ) {
        tmp = (List)malloc( sizeof(struct ListNode) );
        fread( tmp, sizeof(tmp->info), 1, fp);
        if( feof(fp) ) {
            printf("读取失败!文件为空!\n");
            free(tmp);
        }
        return(NULL);
    }

    while ( feof(fp) == 0 ) {
        tmp = (List)malloc( sizeof(struct ListNode) ); 
        fread( tmp, sizeof(tmp->info), 1, fp);
        printf("正在读取第%d个数据\n", ++i);
        if ( feof(fp) != 0 ) {
            /* reached end */
            free(tmp); break;
        }
        /*  List tail insert */ 
        P->next = tmp;
        P = tmp;
        P->next = NULL;
    }
    fclose(fp);
    printf("Read successfulluy!\n");
    return L;
}