用c写一个一元多项式的表示和相减、相加

好的，以下是用C语言实现一元多项式的表示和相加、相减的代码：

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

typedef struct PolyNode *Polynomial;
struct PolyNode {
    int coef; // 系数
    int expon; // 指数
    Polynomial next; // 指向下一个节点的指针
};

// 创建一个新的节点
Polynomial newNode(int coef, int expon) {
    Polynomial p = (Polynomial)malloc(sizeof(struct PolyNode));
    p->coef = coef;
    p->expon = expon;
    p->next = NULL;
    return p;
}

// 将多项式插入到链表中
void insert(Polynomial *p, int coef, int expon) {
    Polynomial node = newNode(coef, expon);
    if (*p == NULL) {
        *p = node;
    } else {
        Polynomial cur = *p;
        while (cur->next != NULL) {
            cur = cur->next;
        }
        cur->next = node;
    }
}

// 释放链表的内存
void freeList(Polynomial p) {
    Polynomial cur = p;
    while (cur != NULL) {
        Polynomial temp = cur;
        cur = cur->next;
        free(temp);
    }
}

// 打印多项式
void printPoly(Polynomial p) {
    if (p == NULL) {
        printf("0\n");
        return;
    }
    while (p != NULL) {
        if (p->coef != 0) {
            printf("%dX^%d", p->coef, p->expon);
            if (p->next != NULL && p->next->coef > 0) {
                printf("+");
            }
        }
        p = p->next;
    }
    printf("\n");
}

// 多项式相加
Polynomial addPoly(Polynomial p1, Polynomial p2) {
    Polynomial result = NULL;
    while (p1 != NULL && p2 != NULL) {
        if (p1->expon > p2->expon) {
            insert(&result, p1->coef, p1->expon);
            p1 = p1->next;
        } else if (p1->expon < p2->expon) {
            insert(&result, p2->coef, p2->expon);
            p2 = p2->next;
        } else {
            int sum = p1->coef + p2->coef;
            if (sum != 0) {
                insert(&result, sum, p1->expon);
            }
            p1 = p1->next;
            p2 = p2->next;
        }
    }
    while (p1 != NULL) {
        insert(&result, p1->coef, p1->expon);
        p1 = p1->next;
    }
    while (p2 != NULL) {
        insert(&result, p2->coef, p2->expon);
        p2 = p2->next;
    }
    return result;
}

// 多项式相减
Polynomial subPoly(Polynomial p1, Polynomial p2) {
    Polynomial result = NULL;
    while (p1 != NULL && p2 != NULL) {
        if (p1->expon > p2->expon) {
            insert(&result, p1->coef, p1->expon);
            p1 = p1->next;
        } else if (p1->expon < p2->expon) {
            insert(&result, -p2->coef, p2->expon);
            p2 = p2->next;
        } else {
            int diff = p1->coef - p2->coef;
            if (diff != 0) {
                insert(&result, diff, p1->expon);
            }
            p1 = p1->next;
            p2 = p2->next;
        }
    }
    while (p1 != NULL) {
        insert(&result, p1->coef, p1->expon);
        p1 = p1->next;
    }
    while (p2 != NULL) {
        insert(&result, -p2->coef, p2->expon);
        p2 = p2->next;
    }
    return result;
}

int main() {
    Polynomial p1 = NULL, p2 = NULL, result = NULL;
    int n1, n2, coef, expon;
    printf("请输入第一个多项式的项数：");
    scanf("%d", &n1);
    printf("请输入第一个多项式的系数和指数：\n");
    for (int i = 0; i < n1; i++) {
        scanf("%d %d", &coef, &expon);
        insert(&p1, coef, expon);
    }
    printf("第一个多项式为：");
    printPoly(p1);
    printf("请输入第二个多项式的项数：");
    scanf("%d", &n2);
    printf("请输入第二个多项式的系数和指数：\n");
    for (int i = 0; i < n2; i++) {
        scanf("%d %d", &coef, &expon);
        insert(&p2, coef, expon);
    }
    printf("第二个多项式为：");
    printPoly(p2);
    result = addPoly(p1, p2);
    printf("两个多项式相加的结果为：");
    printPoly(result);
    freeList(result);
    result = subPoly(p1, p2);
    printf("两个多项式相减的结果为：");
    printPoly(result);
    freeList(result);
    freeList(p1);
    freeList(p2);
    return 0;
}

希望这个代码能够帮到你！