SIMS-LITE

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

#define MAX_STUDENTS 100

typedef struct { char id[20]; // 学号 char name[50]; // 姓名 float score; // 成绩 } Student;

typedef struct { Student students[MAX_STUDENTS]; int length; // 当前学生数量 } StudentList;

// 初始化学生列表 void InitList(StudentList *L) { L->length = 0; }

// (1) 逐个输入学生信息 void InputStudents(StudentList *L) { int n; printf("请输入学生人数(不超过%d): ", MAX_STUDENTS); scanf("%d", &n);

if (n <= 0 || n > MAX_STUDENTS) {
    printf("输入人数不合法!\n");
    return;
}

for (int i = 0; i < n; i++) {
    printf("请输入第%d个学生的信息:\n", i+1);
    printf("学号: ");
    scanf("%s", L->students[L->length].id);
    printf("姓名: ");
    scanf("%s", L->students[L->length].name);
    printf("成绩: ");
    scanf("%f", &L->students[L->length].score);
    L->length++;
}
printf("输入完成!\n");

}

// (2) 显示所有学生信息 void DisplayStudents(StudentList *L) { if (L->length == 0) { printf("没有学生信息!\n"); return; }

printf("学号\t姓名\t成绩\n");
printf("----------------------------\n");
for (int i = 0; i < L->length; i++) {
    printf("%s\t%s\t%.1f\n", 
           L->students[i].id, 
           L->students[i].name, 
           L->students[i].score);
}

}

// (3) 在指定位置插入学生信息 void InsertStudent(StudentList *L) { if (L->length >= MAX_STUDENTS) { printf("学生列表已满，无法插入!\n"); return; }

int pos;
printf("请输入要插入的位置(1-%d): ", L->length + 1);
scanf("%d", &pos);

if (pos < 1 || pos > L->length + 1) {
    printf("位置不合法!\n");
    return;
}

Student s;
printf("请输入学生信息:\n");
printf("学号: ");
scanf("%s", s.id);
printf("姓名: ");
scanf("%s", s.name);
printf("成绩: ");
scanf("%f", &s.score);

// 将pos-1之后的元素后移
for (int i = L->length; i >= pos; i--) {
    L->students[i] = L->students[i-1];
}

L->students[pos-1] = s;
L->length++;
printf("插入成功!\n");

}

// (4) 删除指定位置的学生记录 void DeleteStudent(StudentList *L) { if (L->length == 0) { printf("学生列表为空，无法删除!\n"); return; }

int pos;
printf("请输入要删除的位置(1-%d): ", L->length);
scanf("%d", &pos);

if (pos < 1 || pos > L->length) {
    printf("位置不合法!\n");
    return;
}

printf("删除的学生信息: %s %s %.1f\n", 
       L->students[pos-1].id, 
       L->students[pos-1].name, 
       L->students[pos-1].score);

// 将pos之后的元素前移
for (int i = pos; i < L->length; i++) {
    L->students[i-1] = L->students[i];
}

L->length--;
printf("删除成功!\n");

}

// (5) 统计学生个数 void CountStudents(StudentList *L) { printf("当前学生人数: %d\n", L->length); }

// 直接插入排序 - 按姓名 void InsertionSortByName(StudentList *L) { int i, j; Student temp;

for (i = 1; i < L->length; i++) {
    temp = L->students[i];
    j = i - 1;
    
    while (j >= 0 && strcmp(L->students[j].name, temp.name) > 0) {
        L->students[j+1] = L->students[j];
        j--;
    }
    
    L->students[j+1] = temp;
}
printf("按姓名排序完成!\n");

}

// 快速排序分区函数 - 按学号 int Partition(StudentList *L, int low, int high) { Student pivot = L->students[low];

while (low < high) {
    while (low < high && strcmp(L->students[high].id, pivot.id) >= 0) {
        high--;
    }
    L->students[low] = L->students[high];
    
    while (low < high && strcmp(L->students[low].id, pivot.id) <= 0) {
        low++;
    }
    L->students[high] = L->students[low];
}

L->students[low] = pivot;
return low;

}

// 快速排序递归函数 - 按学号 void QuickSort(StudentList *L, int low, int high) { if (low < high) { int pivotpos = Partition(L, low, high); QuickSort(L, low, pivotpos - 1); QuickSort(L, pivotpos + 1, high); } }

// (6) 排序功能 void SortStudents(StudentList *L) { if (L->length == 0) { printf("没有学生信息，无法排序!\n"); return; }

int choice;
printf("请选择排序方式:\n");
printf("1. 按姓名排序(直接插入排序)\n");
printf("2. 按学号排序(快速排序)\n");
printf("请选择: ");
scanf("%d", &choice);

switch (choice) {
    case 1:
        InsertionSortByName(L);
        break;
    case 2:
        QuickSort(L, 0, L->length - 1);
        printf("按学号排序完成!\n");
        break;
    default:
        printf("无效选择!\n");
}

}

// (7) 折半查找 - 按学号 void BinarySearchById(StudentList *L) { if (L->length == 0) { printf("没有学生信息，无法查找!\n"); return; }

// 先确保按学号有序
QuickSort(L, 0, L->length - 1);

char targetId[20];
printf("请输入要查找的学号: ");
scanf("%s", targetId);

int low = 0, high = L->length - 1, mid;
while (low <= high) {
    mid = (low + high) / 2;
    
    int cmp = strcmp(L->students[mid].id, targetId);
    if (cmp == 0) {
        printf("查找成功!\n");
        printf("学号: %s, 姓名: %s, 成绩: %.1f\n", 
               L->students[mid].id, 
               L->students[mid].name, 
               L->students[mid].score);
        return;
    } else if (cmp < 0) {
        low = mid + 1;
    } else {
        high = mid - 1;
    }
}

printf("未找到学号为 %s 的学生!\n", targetId);

}

// 显示菜单 void ShowMenu() { printf("\n简易学生信息管理系统\n"); printf("1. 输入学生信息\n"); printf("2. 显示所有学生信息\n"); printf("3. 插入学生信息\n"); printf("4. 删除学生信息\n"); printf("5. 统计学生人数\n"); printf("6. 排序学生信息\n"); printf("7. 查找学生信息\n"); printf("0. 退出系统\n"); printf("请选择操作: "); }

int main() { StudentList list; InitList(&list);

int choice;
do {
    ShowMenu();
    scanf("%d", &choice);
    
    switch (choice) {
        case 1:
            InputStudents(&list);
            break;
        case 2:
            DisplayStudents(&list);
            break;
        case 3:
            InsertStudent(&list);
            break;
        case 4:
            DeleteStudent(&list);
            break;
        case 5:
            CountStudents(&list);
            break;
        case 6:
            SortStudents(&list);
            break;
        case 7:
            BinarySearchById(&list);
            break;
        case 0:
            printf("感谢使用，再见!\n");
            break;
        default:
            printf("无效选择，请重新输入!\n");
    }
} while (choice != 0);

return 0;

}