请你用C语言写一个学生信息管理系统包括查询，删除，添加，排序

我可以回答这个问题。以下是一个简单的学生信息管理系统的C语言代码示例，包括查询、删除、添加和排序功能：

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

#define MAX_STUDENTS 100

struct student {
char name[20];
int id;
float gpa;
};

struct student students[MAX_STUDENTS];
int num_students = 0;

void add_student() {
if (num_students >= MAX_STUDENTS) {
printf("Error: too many students\n");
return;
}
struct student s;
printf("Enter name: ");
scanf("%s", s.name);
printf("Enter ID: ");
scanf("%d", &s.id);
printf("Enter GPA: ");
scanf("%f", &s.gpa);
students[num_students] = s;
num_students++;
printf("Student added.\n");
}

void print_student(struct student s) {
printf("%s (ID: %d, GPA: %.2f)\n", s.name, s.id, s.gpa);
}

void print_students() {
if (num_students == 0) {
printf("No students.\n");
return;
}
printf("Students:\n");
for (int i = 0; i < num_students; i++) {
printf("%d. ", i+1);
print_student(students[i]);
}
}

void find_student() {
int id;
printf("Enter ID: ");
scanf("%d", &id);
for (int i = 0; i < num_students; i++) {
if (students[i].id == id) {
printf("Found student:\n");
print_student(students[i]);
return;
}
}
printf("Student not found.\n");
}

void delete_student() {
int id;
printf("Enter ID: ");
scanf("%d", &id);
for (int i = 0; i < num_students; i++) {
if (students[i].id == id) {
for (int j = i; j < num_students-1; j++) {
students[j] = students[j+1];
}
num_students--;
printf("Student deleted.\n");
return;
}
}
printf("Student not found.\n");
}

int compare_students(const void* a, const void* b) {
struct student* s1 = (struct student*) a;
struct student* s2 = (struct student*) b;
if (s1->gpa > s2->gpa) {
return -1;
} else if (s1->gpa < s2->gpa) {
return 1;
} else {
return 0;
}
}

void sort_students() {
qsort(students, num_students, sizeof(struct student), compare_students);
printf("Students sorted by GPA.\n");
}

int main() {
int choice;
while (1) {
printf("\n");
printf("1. Add student\n");
printf("2. Print students\n");
printf("3. Find student\n");
printf("4. Delete student\n");
printf("5. Sort students\n");
printf("6. Quit\n");
printf("Enter choice: ");
scanf("%d", &choice);
switch (choice) {
case 1:
add_student();
break;
case 2:
print_students();
break;
case 3:
find_student();
break;
case 4:
delete_student();
break;
case 5:
sort_students();
break;
case 6:
exit(0);
default:
printf("Invalid choice.\n");
}
}
return 0;
}