• 直接上代码不解释

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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define AVAILABLE 0
#define UNAVAILABLE 1
#define MAXNAME 30
#define CLEAR "cls"typedef struct book{char *name;int id;int count;int status;struct book *next;
}Book;void welcome();
void error(char *);           // [异常提醒]
char land();                  // [主页面项目]
int usrstudent();             // [学生入口]返回 0表示返回主页 1表示继续执行本函数
int usrmanager();             // [管理员入口]返回 0表示返回主页 1表示继续执行本函数
int viewbook();               // [查看图书]返回打印的图书个数     失败返回-1
int addbook();                // [注册图书]添加图书成功 返回图书id  失败返回-1
int modbook();                // [修改图书]修改图书信息   成功后返回id  失败 -1
int delbook();                // [注销图书]删除成功 返回被删除图书的id 失败返回-1
void printbook(Book *);       // [打印图书]
Book *lookup(char *, int);    // [搜索图书]
int borrowbook();             // [借阅图书]
int returnbook();             // [归还图书]

Book *head = NULL;
int nbook = 0;
int main(){welcome();return 0;
}
void welcome(){printf("*************************欢迎使用图书管理系统*************************\n");while(1){printf("-------------------------------------\n");printf("请输入项目前编号执行相关操作：\n");printf("\n[1] 管理员入口\n\n[2] 学生入口\n\n[0] 退出\n\n");switch(land()){case '1':while(1){if(usrmanager()){continue;}else{break;}}break;case '2':while(1){if(usrstudent()){continue;}else{break;}}break;case '0':exit(0);default:error("采集项目参数失败");}}
}
char land(){char c, flag;int i;while(1){for(i = 0; (c = getchar()) != '\n'; flag = c, ++i);if(i == 1){if(flag == '1' || flag == '2' || flag == '0'){return flag;}}else if(i == 0){continue;}error("[请输入命令： 1 / 2 / 0 选择项目]");}return '\0';
}
void error(char *s){fprintf(stderr, "%s\n", s);
}
char dostudent(){char c, flag;int i;while(1){for(i = 0; (c = getchar()) != '\n'; flag = c, ++i );if(i == 1){if(flag == '1' || flag == '2' || flag == '3' || flag == '0'){return flag;}}else if(i == 0){continue;}error("[请输入命令： 1 / 2 / 3/ 0 选择项目]");}
}
int usrstudent(){printf("-------------------------------------\n");printf("请输入项目前编号执行相关操作：\n\n");printf("[1] 借阅图书\n[2] 归还图书\n[3] 查看馆存图书\n");printf("[0] 返回主页\n");switch(dostudent()){case '1':borrowbook();break;case '2':returnbook();break;case '3':viewbook();break;case '0':return 0;default:error("采集项目参数失败");break;}return 1;
}
int borrowbook(){system(CLEAR);char sname[MAXNAME];printf("搜索图书:\n");scanf("%s", sname);getchar();Book *bp;char *namep = NULL;if((bp = lookup(namep = strdup(sname), 0)) == NULL){printf("图书 %s 不存在\n", namep);fflush(stdin);return -1;}else{printbook(bp);if(! bp->status){printf("借阅图书： Y N\n");}else{printf("图书外借中\n");return 0;}while(1){char c = '\0';scanf("%c", &c);getchar();if(!(c == 'Y' || c == 'y' || c == 'N' || c == 'n')){fflush(stdin);error("指令无效");continue;}if(c == 'Y' || c == 'y'){--bp->count > -1 ? printf("成功\n") : printf("失败\n");if(! bp->count){bp->status = UNAVAILABLE;}return bp->id;}else{return 0;}}}  return -1;
}
int returnbook(){system(CLEAR);char sname[MAXNAME];printf("归还图书：\n");scanf("%s", sname);getchar();Book *bp;char *namep;if((bp = lookup(namep = strdup(sname), 0)) == NULL){fflush(stdin);printf("此图书并不是馆内图书\n");return -1;}else{printbook(bp);printf("归还图书： Y N\n");while(1){char c = '\0';scanf("%c", &c);getchar();if(!(c == 'Y' || c == 'y' || c == 'N' || c == 'n')){fflush(stdin);error("指令无效");}else if(c == 'Y' || c == 'y'){bp->count++ ? : (bp->status = AVAILABLE);printf("成功\n");return bp->id;}else{return 0;}}}return -1;
}
char domanager(){char c, flag;int i;while(1){for(i = 0; (c = getchar()) != '\n'; flag = c, ++i);if(i == 1){if(flag == '1' || flag == '2' || flag == '3' || flag == '4' || flag == '0'){return flag;}}else if(i == 0){continue;}error("[请输入命令： 1 / 2 / 3/ 4 / 0 选择项目]");}return '\0';
}
int usrmanager(){printf("-------------------------------------\n");printf("请输入项目前编号执行相关操作：\n\n");printf("[1] 查看已存图书\n[2] 注册新图书\n[3] 修改已有图书信息\n[4] 注销现存图书\n");printf("[0] 返回主页\n");switch(domanager()){case '1':viewbook();break;case '2':addbook();break;case '3':modbook();break;case '4':delbook();break;case '0':return 0;default:error("采集项目参数失败");break;}return 1;}
int viewbook(){system(CLEAR);      ///////////////////////////////////////////Book *bp;for(bp =head; bp != NULL; bp = bp->next){printbook(bp);}if(nbook){return nbook;}else{printf("图书馆还没有图书哦\n");return 0;}return -1;
}
void printbook(Book *bp){printf("图书编号：%d\n", bp->id);printf("图书名：%s\n", bp->name);printf("图书存数：%d\n", bp->count);printf("图书状态：%s\n", bp->status ? "不可借" : "可借");
}
int addbook(){system(CLEAR);      ///////////////////////////////////////////char sname[MAXNAME];int id, count;char *namep;while(1){id = 0;count = 0;namep = NULL;printf("请输入图书名：\n");scanf("%s", sname);getchar();printf("请输入小于1000的图书编号：\n");scanf("%d", &id);getchar();if(!(id > 0 && id < 1000)){error("输入编号不符合要求");fflush(stdin);continue;}printf("请输入小于50的图书数量：\n");scanf("%d", &count);getchar();if(!(count > 0 && count < 50)){error("输入数目不符合要求");fflush(stdin);continue;}Book *bp;        if((bp = lookup(namep = strdup(sname), id)) == NULL){bp = (Book *)malloc(sizeof (Book));if(bp == NULL || (bp->name = namep) == NULL){error("注册图书失败");fflush(stdin);continue;}bp->id = id;bp->count = count;bp->status = AVAILABLE;++nbook;bp->next = head;head = bp;printf("图书 %s 注册成功\n", sname);return id;}else{fflush(stdin);error("图书名或编号已经被占用");}}return -1;
}
Book *lookup(char *s, int id){Book *bp;for(bp = head; bp != NULL; bp = bp->next){if(id == bp->id || strcmp(s, bp->name) == 0){return bp;}}return NULL;
}
int modbook(){  // 修改除id之外的信息  因为要修改id 直接删掉后重新添加会更好system(CLEAR);      ///////////////////////////////////////////Book *bp = NULL;while(1){int id = 0;printf("请输入要修改信息的图书编号：\n");scanf("%d", &id);getchar();if(!(id > 0 && id < 1000)){fflush(stdin);error("图书编号不符合要求");continue;}if((bp = lookup("", id)) != NULL){printf("以下为要修改的图书的现有信息：\n");printbook(bp);printf("[1] 修改图书名\n[2] 修改图书数量\n[3] 修改图书状态\n[0] 放弃修改\n");while(1){int i;scanf("%d", &i);getchar();if(!(i == 1 || i == 2 || i == 3 || i == 0)){fflush(stdin);error("输入项目前编号选择相关项目");continue;}switch(i){case 1:while(1){char newname[MAXNAME], *namep;printf("图书名：\n");scanf("%s", newname);getchar();if((lookup(namep = strdup(newname), 0)) != NULL){fflush(stdin);error("图书名已存在");continue;}if((bp->name = namep) != NULL){printf("修改成功\n");return id;}}break;case 2:while(1){int bnum;printf("输入图书数量：\n");scanf("%d", &bnum);getchar();if(!(bnum > 0 || bnum < 1000)){fflush(stdin);error("数目不符合要求");continue;}bp->count = bnum;printf("修改成功\n");return id;}break;case 3:while(1){char c;int status;status = bp->status;status == AVAILABLE ? printf("修改状态为[不可借]： Y N\n") : printf("修改状态为[可借]： Y N\n");scanf("%c", &c);getchar();if(!( c == 'Y' || c == 'y' || c == 'N' || c == 'n')){fflush(stdin);error("指令无效");continue;}if(c == 'Y' || c == 'y'){status == AVAILABLE ? bp->status = UNAVAILABLE : (bp->status = AVAILABLE);printf("修改成功\n");return id;}else{printf("放弃修改\n");return 0;}}break;case 0:return 0;default:error("获取参数失败");break;   }}}else{printf("没有此图书\n");return 0;}}return -1;
}
int delbook(){system(CLEAR);      ///////////////////////////////////////////Book *bp, *fbp;int id = 0;printf("请输入要注销的图书编号：\n");scanf("%d", &id);getchar();if(!(id > 0 && id < 1000)){fflush(stdin);error("图书编号不符合要求");return -1;}for(fbp = bp = head; bp != NULL; fbp = bp, bp = bp->next){if(bp->id == id){printbook(bp);break;}}if(bp != NULL){while(1){printf("确定要注销此图书：Y  N\n");char YN;scanf("%c", &YN);getchar();if(!((YN == 'Y' || YN == 'y') || (YN == 'N' || YN == 'n'))){fflush(stdin);error("指令无效\n");continue;}if(YN == 'Y' || YN == 'y'){bp == head ? head = bp->next : (fbp->next = bp->next);
                free(bp->name);                                         //2018-05-26修改：添加释放name这块内存//bp内存的只是指向name的指针free(bp);
                bp = NULL;printf("图书注销成功\n");break;}else{printf("放弃注销\n");return 0;}}  return id;}else{printf("要注销的图书编号不存在\n");return -1;}return -1;
}

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• 效果展示

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