输入一个整数n，再使用malloc函数申请nsizeof(struct Student)大小的内存空间，对n个struct Student类型的元素赋值，并显示。使用free函数释放该内存空间，在此基础上，为结构体struct Item类型增加struct Item next成员。并以此为结点，使用malloc函数动态建立多项式单链表。程序结束前使用free函数释放单链表所有结点。用c语言编写且有主函数，输出完整代码

好的，这是您的问题的答案，代码如下：

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

struct Student {
    char name[20];
    int age;
};

struct Item {
    double coef;
    int exp;
    struct Item *next;
};

void display_students(struct Student *p, int n) {
    for (int i = 0; i < n; i++) {
        printf("Student %d: Name: %s, Age: %d\n", i+1, p[i].name, p[i].age);
    }
}

void free_students(struct Student *p) {
    free(p);
}

struct Item* create_node(double coef, int exp) {
    struct Item *node = (struct Item*) malloc(sizeof(struct Item));
    node->coef = coef;
    node->exp = exp;
    node->next = NULL;
    return node;
}

void add_node(struct Item **head, double coef, int exp) {
    struct Item *new_node = create_node(coef, exp);
    if (*head == NULL) {
        *head = new_node;
    } else {
        struct Item *p = *head;
        while (p->next != NULL) {
            p = p->next;
        }
        p->next = new_node;
    }
}

void display_poly(struct Item *head) {
    struct Item *p = head;
    while (p != NULL) {
        printf("%.2fx^%d ", p->coef, p->exp);
        p = p->next;
        if (p != NULL) {
            printf("+ ");
        }
    }
    printf("\n");
}

void free_poly(struct Item *head) {
    struct Item *p = head;
    while (p != NULL) {
        struct Item *q = p;
        p = p->next;
        free(q);
    }
}

int main() {
    int n;
    printf("Input the number of Students: ");
    scanf("%d", &n);

    struct Student *students = (struct Student*) malloc(n * sizeof(struct Student));
    for (int i = 0; i < n; i++) {
        printf("Input the name of Student %d: ", i+1);
        scanf("%s", students[i].name);
        printf("Input the age of Student %d: ", i+1);
        scanf("%d", &students[i].age);
    }

    printf("Displaying students info:\n");
    display_students(students, n);

    free_students(students);

    struct Item *head = NULL;
    add_node(&head, 2.5, 3);
    add_node(&head, 1.2, 2);
    add_node(&head, 3.4, 1);
    add_node(&head, 1.0, 0);

    printf("Displaying polynomial: ");
    display_poly(head);

    free_poly(head);

    return 0;
}

希望能够帮到您！