c语言 求两个多项式的和(1)编写函数实现一个多项式的输入,先输入非零项的个数，再输入每一对非零项系数和指数，返回多项式链表的头指针。(2)编写函数实现两个多项式相加,返回结果多项式链表的头指针。(3)编写函数输出和的每一对非零项系数和指数(4)在main函数中分别调用上述函数。

下面是实现这些功能的C语言代码：

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

// 定义多项式项的结构体
typedef struct PolyNode {
    int coef;  // 系数
    int expon; // 指数
    struct PolyNode *next;
} PolyNode, *Polynomial;

// 从标准输入读入多项式，返回多项式链表的头指针
Polynomial read_poly() {
    int n; // 非零项的个数
    scanf("%d", &n);
    Polynomial head = (Polynomial)malloc(sizeof(PolyNode));
    head->next = NULL;
    Polynomial tail = head;
    while (n--) {
        int coef, expon;
        scanf("%d %d", &coef, &expon);
        if (coef != 0) {
            Polynomial node = (Polynomial)malloc(sizeof(PolyNode));
            node->coef = coef;
            node->expon = expon;
            node->next = NULL;
            tail->next = node;
            tail = node;
        }
    }
    return head;
}

// 将两个多项式相加，返回结果多项式链表的头指针
Polynomial add_poly(Polynomial p1, Polynomial p2) {
    Polynomial head = (Polynomial)malloc(sizeof(PolyNode));
    head->next = NULL;
    Polynomial tail = head;
    while (p1 && p2) {
        if (p1->expon > p2->expon) {
            tail->next = p1;
            p1 = p1->next;
        } else if (p1->expon < p2->expon) {
            tail->next = p2;
            p2 = p2->next;
        } else {
            int coef = p1->coef + p2->coef;
            if (coef != 0) {
                Polynomial node = (Polynomial)malloc(sizeof(PolyNode));
                node->coef = coef;
                node->expon = p1->expon;
                node->next = NULL;
                tail->next = node;
                tail = node;
            }
            p1 = p1->next;
            p2 = p2->next;
        }
    }
    if (p1) {
        tail->next = p1;
    }
    if (p2) {
        tail->next = p2;
    }
    return head->next;
}

// 输出多项式
void print_poly(Polynomial poly) {
    if (poly == NULL) {
        printf("0 0\n");
        return;
    }
    while (poly) {
        printf("%d %d", poly->coef, poly->expon);
        poly = poly->next;
        if (poly) {
            printf(" ");
        }
    }
    printf("\n");
}

int main() {
    // 输入两个多项式
    printf("请输入第一个多项式（非零项的个数，每一对非零项系数和指数）：\n");
    Polynomial p1 = read_poly();
    printf("请输入第二个多项式（非零项的个数，每一对非零项系数和指数）：\n");
    Polynomial p2 = read_poly();

    // 计算两个多项式的和
    Polynomial sum = add_poly(p1, p2);

    // 输出结果
    printf("两个多项式的和为：\n");
    print_poly(sum);

    // 释放内存
    free(p1);
    free(p2);
    free(sum);
    return 0;
}