用c语言写代码：题目要求： 一、定义结构体类型： 每个同学的信息：学号、姓名(英文、无重名)、性别(英文)、三门课程成绩（语文、数学、英语） 二、功能要求： 运行后，显示如下信息，提示输入数字，并运行数字所对应的功能，如：按1，执行“显示所有同学的信息”；按6,执行“删除一个同学”。 1.显示所有同学的信息 2.查找指定姓名的信息 （模糊查找：输入姓名中任何一个或多个文字，比如：输入“zhang”，就显示所有姓名中含“zhang”的信息） 3.显示有不及格同学的信息 4.按指定课程排序输出 5.增加一个新同学 6.修改指定姓名的信息 7.删除指定姓名的信息 0.退出 说明： 1、学生信息不要增加额外的限制，比如：学号不要限制必须要8位。 3、学生信息显示在一行。 4、预先初始化几个学生的基本信息，在此基础上增删改。学生初始化信息，放在程序的第一页，便于修改。 5、菜单能循环显示，即完成一次功能选择后，显示相应结果，再显示菜单。

下面是用C语言实现的代码，实现了题目要求的各种功能：

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

#define MAX_STUDENT_NUM 100

typedef struct {
    int id;             // 学号
    char name[20];      // 姓名
    char gender[10];    // 性别
    int score[3];       // 三门课程成绩
} Student;

Student students[MAX_STUDENT_NUM] = {
        {1001, "Tom", "Male", {85, 90, 80}},
        {1002, "Jerry", "Male", {70, 75, 85}},
        {1003, "Mary", "Female", {80, 65, 90}},
        {1004, "Lisa", "Female", {90, 85, 80}},
        {0, "", "", {0, 0, 0}}   // 结束标志
};

int student_num = 4;    // 当前学生数量

// 显示所有同学的信息
void show_all_students() {
    printf("id\tname\tgender\tchinese\tmath\tenglish\n");
    printf("-------------------------------------------------\n");
    for (int i = 0; i < student_num; i++) {
        if (students[i].id == 0) break;
        printf("%d\t%s\t%s\t%d\t%d\t%d\n", students[i].id, students[i].name,
               students[i].gender, students[i].score[0],
               students[i].score[1], students[i].score[2]);
    }
}

// 模糊查找指定姓名的信息
void search_student(char *name) {
    printf("id\tname\tgender\tchinese\tmath\tenglish\n");
    printf("-------------------------------------------------\n");
    for (int i = 0; i < student_num; i++) {
        if (students[i].id == 0) break;
        if (strstr(students[i].name, name) != NULL) {
            printf("%d\t%s\t%s\t%d\t%d\t%d\n", students[i].id, students[i].name,
                   students[i].gender, students[i].score[0],
                   students[i].score[1], students[i].score[2]);
        }
    }
}

// 显示有不及格同学的信息
void show_failed_students() {
    printf("id\tname\tgender\tchinese\tmath\tenglish\n");
    printf("-------------------------------------------------\n");
    for (int i = 0; i < student_num; i++) {
        if (students[i].id == 0) break;
        if (students[i].score[0] < 60 || students[i].score[1] < 60 || students[i].score[2] < 60) {
            printf("%d\t%s\t%s\t%d\t%d\t%d\n", students[i].id, students[i].name,
                   students[i].gender, students[i].score[0],
                   students[i].score[1], students[i].score[2]);
        }
    }
}

// 按指定课程排序输出
void sort_students(int course) {
    for (int i = 0; i < student_num - 1; i++) {
        for (int j = 0; j < student_num - i - 1; j++) {
            if (students[j].score[course] < students[j + 1].score[course]) {
                Student temp = students[j];
                students[j] = students[j + 1];
                students[j + 1] = temp;
            }
        }
    }
    printf("id\tname\tgender\tchinese\tmath\tenglish\n");
    printf("-------------------------------------------------\n");
    for (int i = 0; i < student_num; i++) {
        if (students[i].id == 0) break;
        printf("%d\t%s\t%s\t%d\t%d\t%d\n", students[i].id, students[i].name,
               students[i].gender, students[i].score[0],
               students[i].score[1], students[i].score[2]);
    }
}

// 增加一个新同学
void add_student() {
    if (student_num >= MAX_STUDENT_NUM) {
        printf("Too many students!\n");
        return;
    }
    printf("Please input the information of the new student:\n");
    printf("id: ");
    scanf("%d", &students[student_num].id);
    printf("name: ");
    scanf("%s", students[student_num].name);
    printf("gender: ");
    scanf("%s", students[student_num].gender);
    printf("chinese score: ");
    scanf("%d", &students[student_num].score[0]);
    printf("math score: ");
    scanf("%d", &students[student_num].score[1]);
    printf("english score: ");
    scanf("%d", &students[student_num].score[2]);
    student_num++;
    printf("New student added successfully.\n");
}

// 修改指定姓名的信息
void modify_student(char *name) {
    for (int i = 0; i < student_num; i++) {
        if (strcmp(students[i].name, name) == 0) {
            printf("Please input the new information of the student:\n");
            printf("id: ");
            scanf("%d", &students[i].id);
            printf("name: ");
            scanf("%s", students[i].name);
            printf("gender: ");
            scanf("%s", students[i].gender);
            printf("chinese score: ");
            scanf("%d", &students[i].score[0]);
            printf("math score: ");
            scanf("%d", &students[i].score[1]);
            printf("english score: ");
            scanf("%d", &students[i].score[2]);
            printf("Student information modified successfully.\n");
            return;
        }
    }
    printf("No such student.\n");
}

// 删除指定姓名的信息
void delete_student(char *name) {
    for (int i = 0; i < student_num; i++) {
        if (strcmp(students[i].name, name) == 0) {
            for (int j = i; j < student_num - 1; j++) {
                students[j] = students[j + 1];
            }
            student_num--;
            printf("Student information deleted successfully.\n");
            return;
        }
    }
    printf("No such student.\n");
}

// 主函数
int main() {
    int choice;
    char name[20];
    while (1) {
        printf("\nPlease input a number to choose a function:\n");
        printf("1. Show all student information\n");
        printf("2. Search student by name\n");
        printf("3. Show failed students\n");
        printf("4. Sort students by course\n");
        printf("5. Add a new student\n");
        printf("6. Modify student information\n");
        printf("7. Delete student information\n");
        printf("0. Exit\n");
        scanf("%d", &choice);
        switch (choice) {
            case 1:
                show_all_students();
                break;
            case 2:
                printf("Please input name: ");
                scanf("%s", name);
                search_student(name);
                break;
            case 3:
                show_failed_students();
                break;
            case 4:
                printf("Please input course number (0 for Chinese, 1 for Math, 2 for English): ");
                scanf("%d", &choice);
                sort_students(choice);
                break;
            case 5:
                add_student();
                break;
            case 6:
                printf("Please input name: ");
                scanf("%s", name);
                modify_student(name);
                break;
            case 7:
                printf("Please input name: ");
                scanf("%s", name);
                delete_student(name);
                break;
            case 0:
                printf("Goodbye!\n");
                exit(0);
            default:
                printf("Invalid choice. Please input again.\n");
        }
    }
    return 0;
}

以上代码实现了题目要求的各种功能，可以根据需要进行修改和优化。