C语言项目(一):学生信息管理系统

实现方式：链表

结构定义

typedef struct MyStu MyStudent;
typedef struct node Node;
typedef Node *pNode;

struct MyStu {
    char name [20];
    int age;
    long ID;
    double score;
};

struct node {
    MyStudent student;
    pNode next;
};

static pNode head = NULL;

基本功能

void InputStudentInformation();

void PrintStudentInformation();

void SaveStudentInformation();

void ReadStudentInformation();

int CountStudentNumber();

pNode FindStudent();

pNode FinePrevious(pNode Cur);

void ModifyStudentInformation();

void DeleteStudentInformation();

void Menu();

void KeyDown();

void SubMenu();

界面

void Menu() {
    printf("********************************************************
");
    printf("==============欢迎使用高校学生成绩管理系统==============
");
    printf("	=============请选择功能列表==============
");
    printf("	**************1.录入学生信息**************
");
    printf("	**************2.输出学生信息**************
");
    printf("	**************3.统计学生人数**************
");
    printf("	**************4.查找学生信息**************
");
    printf("	**************5.修改学生信息**************
");
    printf("	**************6.删除学生信息**************
");
    printf("	**************0.退 出 系 统**************
");
    printf("********************************************************
");
}

菜单实现

void KeyDown() {
    int choice;
    printf("Function to chose (0~6):
");
    scanf("%d", &choice);
    switch (choice) {
        case 1:
            InputStudentInformation();
            SaveStudentInformation();
            break;
        case 2:
            PrintStudentInformation();
            break;
        case 3:
            printf("Total students is %d
", CountStudentNumber());
            break;
        case 4:
        {
            pNode Find = FindStudent();
            if (Find != NULL) {
                printf("NUM:%ld	NAME:%s	AGE:%d	SCORE:%lf",
                       Find->student.ID,
                       Find->student.name,
                       Find->student.age,
                       Find->student.score);
            }
            break;
        }
        case 5:
            ModifyStudentInformation();
            SaveStudentInformation();
            break;
        case 6:
            DeleteStudentInformation();
            SaveStudentInformation();
            break;
        case 0:
            printf("Welcome to use again!");
            exit(0);
        default:
            printf("Invalid Input!");
            break;
    }
}

子菜单

void SubMenu() {
    printf("********************************************************
");
    printf("==============欢迎使用高校学生成绩管理系统==============
");
    printf("	=============请选择功能列表==============
");
    printf("	**************a.修改姓名**************
");
    printf("	**************b.修改学号**************
");
    printf("	**************c.修改年龄**************
");
    printf("	**************d.修改成绩**************
");
    printf("	**************q.退出系统**************
");
    printf("********************************************************
");
}

打印功能

void PrintStudentInformation() {
    system("cls");
    printf("********************************************************
");
    printf("==============欢迎使用高校学生成绩管理系统==============
");
    printf("********************************************************
");
    pNode tmp = head->next;
    while (tmp != NULL) {
        printf("NUM:%ld	NAME:%s	AGE:%d	SCORE:%lf
",
               tmp->student.ID,
               tmp->student.name,
               tmp->student.age,
               tmp->student.score);
        tmp = tmp->next;

    }
}

保存功能

void SaveStudentInformation() {
    FILE *fp = fopen(PATH, "w+");
    if (!fp) {
        printf("FAIL");
        exit(0);
    }
    pNode tmp;
    tmp = head->next;
    while (tmp != NULL) {
        fwrite(&tmp->student, sizeof(Node), 1, fp);
        tmp = tmp->next;
    }
    fclose(fp);
    printf("SAVE DONE!");
}

读取功能

void ReadStudentInformation() {
    FILE *read = fopen(PATH, "r");
    if (!read) {
        printf("FAIL");
        exit(0);
    }
    MyStudent stu;
    while (fread(&stu, sizeof(MyStudent), 1, read)) {
        pNode tmp = (pNode)malloc(sizeof(Node));
        memcpy(tmp, &stu, sizeof(MyStudent));
        if (head->next == NULL) {
            head->next = tmp;
            tmp->next = NULL;
        }
        else {
            pNode tmp_ = head->next;
            head->next = tmp;
            tmp->next = tmp_;
        }
    }
    fclose(read);
    printf("LOAD DONE!");
}

计数功能

int CountStudentNumber() {
    int cnt = 0;
    pNode tmp;
    tmp = head->next;
    while (tmp != NULL) {
        cnt++;
        tmp = tmp->next;
    }
    return cnt;
}

增删改查

void InputStudentInformation() {
    pNode NewNode = (pNode)malloc(sizeof(Node));
    if (head==NULL) {
        head = (pNode)malloc(sizeof(Node));
        head->next = NewNode;
        NewNode->next = NULL;
    }
    else {
        pNode tmp = head->next;
        head->next = NewNode;
        NewNode->next = tmp;
    }
    printf("Name:
");
    scanf("%s", NewNode->student.name);
    printf("NUM:
");
    scanf("%ld", &NewNode->student.ID);
    printf("AGE:
");
    scanf("%d", &NewNode->student.age);
    printf("SCORE:
");
    scanf("%lf", &NewNode->student.score);
    printf("DONE");
}
pNode FindStudent() {
    printf("Enter student ID:
");
    long id_f;
    scanf("%ld", &id_f);
    pNode tmp;
    tmp = head->next;
    while (tmp != NULL) {
        if (tmp->student.ID == id_f) {
            return tmp;
        }
        tmp = tmp->next;
    }
    printf("ERROR ID! 
");
    return NULL;
}
pNode FinePrevious(pNode Cur) {
    pNode tmp;
    tmp = head;
    while (tmp != NULL) {
        if (tmp->next == Cur) {
            return tmp;
        }
        tmp = tmp->next;
    }
    return NULL;
}
void ModifyStudentInformation() {
    pNode Find = FindStudent();
    if (Find == NULL) {
        printf("ID ERROR!");
        return;
    }
    SubMenu();
    char ch;
    scanf("%c", &ch);
    switch (ch) {
        case 'a':
            printf("Enter new name:
");
            scanf("%s", Find->student.name);
            printf("MODIFY DONE!
");
            break;
        case 'b':
            printf("Enter new ID:
");
            scanf("%ld", &Find->student.ID);
            printf("MODIFY DONE!
");
            break;
        case 'c':
            printf("Enter new age:
");
            scanf("%d", &Find->student.age);
            printf("MODIFY DONE!
");
            break;
        case 'd':
            printf("Enter new score:
");
            scanf("%lf", &Find->student.score);
            printf("MODIFY DONE!
");
            break;
        case 'q':
            printf("Welcome to using this system again!");
            break;
        default:
            printf("Invalid Input");
            break;
    }
}
void DeleteStudentInformation() {
    pNode Cur = FindStudent();
    if (Cur == NULL) {
        return;
    }
    pNode Prev = FinePrevious(Cur);
    if (Cur->next == NULL) {
        Prev->next = NULL;
        free(Cur);
    }
    else {
        pNode tmp = Cur->next;
        Cur->next = NULL;
        Prev->next = tmp;
        free(Cur);
    }

}