学生成绩管理系统C（链表）语言

#include"stdio.h"
#include"stdlib.h"
#include"string.h"  //用于调用一些函数
struct person {
    char name[20];
    int ID;
    int chinese;
    int english;
    int math;
    struct person *next;   //连接处的指针
};                                 //由于create里面就有initialize所以先把initialize放在前面

void initialize(struct person *p, int num) {  //初始化链表里面的值
    printf("innitialize person %d
 name is:", num);  //num用于计入输入的第几个同学
    scanf_s("%s", &p->name, sizeof(p->name));
    getchar();
    printf("ID:");
    scanf_s("%d", &p->ID);
    getchar();
    printf("chinese:");
    scanf_s("%d", &p->chinese);
    getchar();
    printf("math:");
    scanf_s("%d", &p->math);
    getchar();
    printf("english:");
    scanf_s("%d", &p->english);
    getchar();
}

struct person *create(int len) {
    int num = 0;
    struct person *h = 0, *c, *pre = 0;
    while (num < len) {
        c = (struct person*)malloc(sizeof(struct person)); //malloc取内存 sizeof为这个内存的大小  然后转化成指针
        if (num == 0) { h = c; pre = c; }  // 如果num=0  h存下了首地址  为以后拿做准备
        c->next = NULL;
        if (num) {
            pre->next = c;  //pre为前一块内存的地址  把后一块的首地址赋给前一块的尾
            pre = c;      //收尾连接后  pre指前一块的功能就完成了  然后再指向现在的内存 为下一次拿内存、赋地址做准备
        }
        initialize(c, num);   //每取一块地址就去输入一次
        ++num;
    }return h;
}
void traverse(struct person *head) {
    int index = 1;    // 用于计数第几个学生
    while (head != NULL) {  //同样一直到后面没有地址结束
        printf("name is: %s	 ID is:%d	  chinese is:%d	  englishi is:%d	  math is:%d
", head->name, head->ID, head->chinese, head->english, head->math);
        head = head->next;  //前一个输完后就要指向下一块地址
        ++index;
    }
}

int getlength(struct person *head) {
    int num = 0;
    while (head != NULL) {    //当head指向后面没有了 它就是NULL  结束
        ++num;
        head = head->next;  //如果head 不是NULL ++num后要把head指针指向最后
    }return num;
}

//增加学生信息
void append_node(struct person *h) {
    struct person *t = h, *p;
    while (t->next != NULL) {      
        t = t->next;
    }p = (struct person *)malloc(sizeof(struct person));
    initialize(p, 0);
    p->next = NULL;    
    t->next = p;
    traverse(h);
}


//删除
struct person * delete_ID(struct person *head, int ID, int len) {
    struct person *t = head;
    struct person *temp;
    for (int i = 0; i < (len - 1); ++i) {
        if (i == 0) {
            if (head->ID == ID) {  head = head->next;  free(t); traverse(head); return head; }
            if ((t->next)->ID == ID) {
                temp = t->next;
                t->next = (t->next)->next;
                free(temp); traverse(head); return head;
            }
        }
        if (i != 0) {
            if ((t->next)->ID == ID) {
                temp = t->next;
                t->next = (t->next)->next;
                free(temp); traverse(head); return head;
            }t = t->next;
        }
    }return head;
}

//学号查询
void search_ID(struct person *head, int ID) {
    while (head != NULL) {
        if (head->ID == ID) {
            printf("name is: %s	 ID is:%d	  chinese is:%d	  englishi is:%d  math is:%d
", head->name, head->ID, head->chinese, head->english, head->math);
        }head = head->next;
    }
}

//姓名查询
void search_name(struct person *head, char name[20]) {
    while (head != NULL) {
        if ((strcmp(head->name, name)) == 0) { printf("name is: %s	 ID is:%d	  chinese is:%d	  englishi is:%d  math is:%d
", head->name, head->ID, head->chinese, head->english, head->math); }
        head = head->next;
    }
}

//指定学生修改
void change(struct person *head, char name[20]) {
    while (head != NULL) {
        if (strcmp(head->name, name) == 0) {
            printf(" name is:");
            scanf_s("%s", &head->name, sizeof(head->name));
            getchar();
            printf("ID:");
            scanf_s("%d", &head->ID);
            getchar();
            printf("chinese:");
            scanf_s("%d", &head->chinese);
            getchar();
            printf("english:");
            scanf_s("%d", &head->english);
            getchar();
            printf("math:");
            scanf_s("%d", &head->math);
            getchar();
        }
        head = head->next;
    }
    traverse(head);
}
//数学分数平均数
int average_math(struct person *head, int len) {
    int i = 0, sum = 0, average;
    struct person *t = head;
    while (t != NULL) {
        sum += t->math;
        t = t->next;
    }
    average = (sum / len);
    return average;
}
//英语分数平均数
int average_english(struct person *head, int len) {
    int i = 0, sum = 0, average;
    struct person *t = head;
    while (t != NULL) {
        sum += t->english;
        t = t->next;
    }
    average = (sum / len);
    return average;
}

//语文分数平均数
int average_chinese(struct person *head, int len) {
    int  sum = 0, average;
    struct person *t = head;
    while (t != NULL) {
        sum += t->chinese;
        t = t->next;
    }
    average = (sum / len);
    return average;
}

//成绩区间统计
int statistics_math(struct person*head, int min, int max) {
    int conter = 0;
    while (head!= NULL) {
        if (head->math >= min&&head->math <= max) {
            ++conter;
            printf("name:%s math score:%d
", head->name, head->math);
        }head = head->next;
    }return conter;
}

int statistics_chinese(struct person*head, int min, int max) {
    int conter = 0;
    while (head != NULL) {
        if (head->chinese >= min&&head->chinese <= max) {
            ++conter;
            printf("name:%s chinese score:%d
", head->name, head->chinese);
        }head = head->next;
    }return conter;
}
int statistics_english(struct person*head, int min, int max) {
    int conter = 0;
    while (head != NULL) {
        if (head->english >= min&&head->english <= max) {
            ++conter;
            printf("name:%s english score:%d
", head->name, head->english);
        }head = head->next;
    }return conter;
}

//某名学生的平均成绩
int average_name(struct person*head, char name[20]) {
    int av = 0;
    while (head != NULL) {
        if (strcmp(head->name, name) == 0) { av += head->math; av += head->chinese; av += head->english; }
        head = head->next;
    }
    av = av / 3;
    return av;
}

//排序数学
void rank_math(struct person *h, int len) {
    struct person  *t = h, *pre = h;
    int i, math, chinese, english,ID;
    char name[20];
    t = t->next;
    for (i = 0; i < (len - 1); ++i) {
        while (t != NULL) {
            if ((t->math) >(pre->math)) {
                ID = t->ID; t->ID = pre->ID; pre->ID = ID;
                math = t->math; t->math = pre->math; pre->math = math;
                strcpy_s(name, t->name); strcpy_s(t->name, pre->name); strcpy_s(pre->name, name);
                chinese = t->chinese; t->chinese = pre->chinese; pre->chinese = chinese;
                english = t->english; t->english = pre->english; pre->english = english;
            }
            t = t->next;
        }pre = pre->next; t = pre->next;
    }
    traverse(h);
}
//排序语文
void rank_chinese(struct person *h, int len) {
    struct person  *t = h, *pre = h;
    int i, math, chinese, english,ID;
    char name[20];
    t = t->next;
    for (i = 0; i < (len - 1); ++i) {
        while (t != NULL) {
            if ((t->chinese) >(pre->chinese)) {
                ID = t->ID; t->ID = pre->ID; pre->ID = ID;
                math = t->math; t->math = pre->math; pre->math = math;
                strcpy_s(name, t->name); strcpy_s(t->name, pre->name); strcpy_s(pre->name, name);
                chinese = t->chinese; t->chinese = pre->chinese; pre->chinese = chinese;
                english = t->english; t->english = pre->english; pre->english = english;
            }
            t = t->next;
        }pre = pre->next; t = pre->next;
    }
    traverse(h);
}

//排序英语
void rank_english(struct person *h, int len) {
    struct person  *t = h, *pre = h;
    int i, math, chinese, english,ID;
    char name[20];
    t = t->next;
    for (i = 0; i < (len - 1); ++i) {
        while (t != NULL) {
            if ((t->english) >(pre->english)) {
                ID = t->ID; t->ID = pre->ID; pre->ID = ID;
                math = t->math; t->math = pre->math; pre->math = math;
                strcpy_s(name, t->name); strcpy_s(t->name, pre->name); strcpy_s(pre->name, name);
                chinese = t->chinese; t->chinese = pre->chinese; pre->chinese = chinese;
                english = t->english; t->english = pre->english; pre->english = english;
            }
            t = t->next;
        }pre = pre->next; t = pre->next;
    }
    traverse(h);
}

void release(struct person *head) {
    struct person *n;   //需要一个指针存着下一个地址
    while (head != NULL) {
        n = head->next;  //把n指向下一块要释放的地址
        free(head);
        head = n;   //然后再把head从前一个地址移到下一个地址
    }
}
//取长度
int getlen(struct person *head) {
    int conter = 0;
    struct person*t = head;
    while (t != NULL) {
        ++conter;
        t = t->next;
    }
    return conter;
}
//存入文件
void openfile(struct person *head, int len) {
    FILE *fp;
    struct person*t = head;
    errno_t err;
    int temp;
    char str[100];
    char s[10];
    if ((err = fopen_s(&fp, "D:\学生信息", "w")) != 0)
    {
        printf("文件打开错误
");
    }
    else
    {
        printf("文件打开成功
");
    }
    for (int i = 0; i < len; ++i) {
        strcpy_s(str, t->name);
        fputs("name:", fp);
        fputs(str, fp);
        fputs(": ", fp);

        fputs("ID:", fp);
        sprintf_s(s, "%d", t->ID);
        fputs(s, fp);
        fputs("  ", fp);

        sprintf_s(s, "%d", t->chinese);
        fputs("chinese:", fp);
        fputs(s, fp);
        fputs("  ", fp);

        sprintf_s(s, "%d", t->math);
        fputs("math:", fp);
        fputs(s, fp);
        fputs("  ", fp);

        sprintf_s(s, "%d", t->english);
        fputs("english:", fp);
        fputs(s, fp);
        fputs("
", fp);
        t = t->next;
    }
    return;
}


void menu(struct person *head, int len) {
    int m = 0;
    int min, max;
    int ID = 0;
    int conter = 0;
    char name[20];
    while (1) {
            printf("                      请选择您需要的操作：
");
            printf("                                       0.  遍历学生信息
");
            printf("                                       1.  增加学生信息
");
            printf("                                       2.  删除学生信息
");
            printf("                                       3.  修改学生信息
");
            printf("                                       4.  按姓名查询
");
            printf("                                       5.  按学号查询
");
            printf("                                       6.  语文成绩在某个区间段的人数以及学生
");
            printf("                                       7.  数学成绩在某个区间段的人数以及学生
");
            printf("                                       8.  英语成绩在某个区间段的人数以及学生
");
            printf("                                       9.  语文平均分
");
            printf("                                       10. 数学平均分
");
            printf("                                       11. 英语平均分
");
            printf("                                       12. 某个学生的三科平均成绩
");
            printf("                                       13. 按语文成绩从高到低排序
");
            printf("                                       14. 按数学成绩从高到低排序
");
            printf("                                       15. 按英语成绩从高到底排序
");
            printf("                                       16. 结束功能并把信息写入文件中
");
            scanf_s("%d", &m);
            switch (m) {
            case 0: traverse(head); break;
            case 1: append_node(head); break;
            case 2: {printf("要删除学生信息的学号:");
                scanf_s("%d", &ID);
                head=delete_ID(head, ID, getlen(head)); }break;
            case 3: {printf("需要修改学生信息的同学姓名：");
                scanf_s("%s", &name, sizeof(name));
                change(head, name); }break;
            case 4: {printf("search by name:");
                scanf_s("%s", &name, sizeof(name));
                search_name(head, name); }break;
            case 5: {printf("学号查询：");
                scanf_s("%d", &ID);
                search_ID(head, ID); }break;
            case 6: {printf("请输入语文成绩的区间:");
                printf("min=");
                scanf_s("%d", &min);
                printf("max=");
                scanf_s("%d", &max);
                printf("语文成绩在区间%d到%d之间的学生：%d人
", min, max, statistics_chinese(head, min, max)); }break;
            case 7: {printf("请输入数学成绩的区间:");
                printf("min=");
                scanf_s("%d", &min);
                printf("max=");
                scanf_s("%d", &max);
                printf("数学成绩在区间%d到%d之间的学生:%d人
", min, max, statistics_math(head, min, max)); }break;
            case 8: {printf("请输入英语成绩的区间:");
                printf("min=");
                scanf_s("%d", &min);
                printf("max=");
                scanf_s("%d", &max);
                printf("英语成绩在区间%d到%d之间的学生:共有%d人
", min, max, statistics_english(head, min, max)); }break;
            case 9: { printf("average of chinese is%d", average_chinese(head, getlen(head))); }break;
            case 10: { printf("average of math is%d", average_math(head, getlen(head))); }break;
            case 11: { printf("average of english is%d", average_english(head, getlen(head))); }break;
            case 12: {printf("请输入学生的姓名：");
                scanf_s("%s", &name, sizeof(name));
                printf("%s 的平均成绩为：%d", name, average_name(head, name)); }break;
            case 13: {printf("按照语文成绩从高到底排序：");
                rank_chinese(head, getlen(head)); }break;
            case 14: {printf("按照数学成绩从高到底排序：");
                rank_math(head, getlen(head)); }break;
            case 15: {printf("按照英语成绩从高到底排序：");
                rank_english(head, getlen(head)); }break;
            case 16: openfile(head, getlen(head)); return;
            }
    }
}

int main() {
    struct person *head;
    int len;
    int min, max;
    int ID = 0;
    char name[20];
    printf("请输入学生信息");
    printf("学生人数:");
    scanf_s("%d", &len);  //输入要取的地址多少
    head = create(len);   // 创建地址   在create里面就有初始复制函数嵌套
    traverse(head);    //遍历
    menu(head, getlen(head));
    release(head);       //释放内存
    system("pause");
    return 0;
}