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.删除指定姓名的信息 2.显示所有不及格的同学，0.退出

好的，以下是定义结构体类型的C语言代码：

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

#define MAX_STUDENTS 100

struct Student {
    int id;
    char name[20];
    char gender[10];
    int scores[3];
};

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 student ID: ");
    scanf("%d", &s.id);
    printf("Enter student name: ");
    scanf("%s", s.name);
    printf("Enter student gender: ");
    scanf("%s", s.gender);
    printf("Enter Chinese score: ");
    scanf("%d", &s.scores[0]);
    printf("Enter Math score: ");
    scanf("%d", &s.scores[1]);
    printf("Enter English score: ");
    scanf("%d", &s.scores[2]);

    for (int i = 0; i < num_students; i++) {
        if (strcmp(students[i].name, s.name) == 0) {
            printf("Error: student name already exists\n");
            return;
        }
    }

    students[num_students++] = s;
    printf("Student added successfully\n");
}

void remove_student() {
    char name[20];
    printf("Enter student name: ");
    scanf("%s", name);

    for (int i = 0; i < num_students; i++) {
        if (strcmp(students[i].name, name) == 0) {
            for (int j = i + 1; j < num_students; j++) {
                students[j - 1] = students[j];
            }
            num_students--;
            printf("Student removed successfully\n");
            return;
        }
    }

    printf("Error: student not found\n");
}

void show_all_students() {
    for (int i = 0; i < num_students; i++) {
        printf("ID: %d, Name: %s, Gender: %s, Scores: %d %d %d\n",
            students[i].id, students[i].name, students[i].gender,
            students[i].scores[0], students[i].scores[1], students[i].scores[2]);
    }
}

void show_failed_students() {
    for (int i = 0; i < num_students; i++) {
        int failed = 0;
        for (int j = 0; j < 3; j++) {
            if (students[i].scores[j] < 60) {
                failed = 1;
                break;
            }
        }
        if (failed) {
            printf("ID: %d, Name: %s, Gender: %s, Scores: %d %d %d\n",
                students[i].id, students[i].name, students[i].gender,
                students[i].scores[0], students[i].scores[1], students[i].scores[2]);
        }
    }
}

int main() {
    int choice;
    do {
        printf("1. Add student\n");
        printf("2. Remove student\n");
        printf("3. Show all students\n");
        printf("4. Show failed students\n");
        printf("0. Quit\n");
        printf("Enter your choice: ");
        scanf("%d", &choice);

        switch (choice) {
            case 1:
                add_student();
                break;
            case 2:
                remove_student();
                break;
            case 3:
                show_all_students();
                break;
            case 4:
                show_failed_students();
                break;
            case 0:
                break;
            default:
                printf("Error: invalid choice\n");
                break;
        }
    } while (choice != 0);

    return 0;
}

这个程序定义了一个 `Student` 结构体类型，包含了学号、姓名、性别和三门课程成绩。程序提供了四个功能：添加学生、删除学生、显示所有学生和显示不及格的学生。用户可以根据提示输入数字，选择要执行的功能。