用c语言写一个数据结构的一元多项式计算器实现加法减法乘法的功能

好的，以下是一个用 C 语言实现的一元多项式计算器，包括加法、减法和乘法功能。它使用链表来存储多项式，每个节点表示一个项，包括系数和指数。其中，每个节点都有一个指向下一个节点的指针。代码如下：

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

/* 多项式项的结构体 */
typedef struct PolyNode {
    int coef;  // 系数
    int expn;  // 指数
    struct PolyNode* next;  // 指向下一个节点的指针
} PolyNode, *PolyList;

/* 创建多项式 */
void createPoly(PolyList* L) {
    int n, coef, expn;
    PolyNode* rear = *L;
    printf("请输入多项式的项数：");
    scanf("%d", &n);
    printf("请依次输入每一项的系数和指数：\n");
    for (int i = 0; i < n; i++) {
        scanf("%d %d", &coef, &expn);
        PolyNode* p = (PolyNode*)malloc(sizeof(PolyNode));
        p->coef = coef;
        p->expn = expn;
        p->next = NULL;
        rear->next = p;
        rear = p;
    }
}

/* 输出多项式 */
void printPoly(PolyList L) {
    PolyNode* p = L->next;
    while (p != NULL) {
        printf("%d x^%d ", p->coef, p->expn);
        if (p->next != NULL) {
            printf("+ ");
        }
        p = p->next;
    }
    printf("\n");
}

/* 多项式相加 */
void addPoly(PolyList La, PolyList Lb, PolyList* Lc) {
    PolyNode *pa = La->next, *pb = Lb->next, *pc;
    *Lc = (PolyNode*)malloc(sizeof(PolyNode));
    pc = *Lc;
    while (pa != NULL && pb != NULL) {
        if (pa->expn < pb->expn) {
            pc->next = pa;
            pc = pa;
            pa = pa->next;
        } else if (pa->expn > pb->expn) {
            pc->next = pb;
            pc = pb;
            pb = pb->next;
        } else {
            int sum = pa->coef + pb->coef;
            if (sum != 0) {
                PolyNode* p = (PolyNode*)malloc(sizeof(PolyNode));
                p->coef = sum;
                p->expn = pa->expn;
                pc->next = p;
                pc = p;
            }
            pa = pa->next;
            pb = pb->next;
        }
    }
    pc->next = (pa != NULL) ? pa : pb;
}

/* 多项式相减 */
void subPoly(PolyList La, PolyList Lb, PolyList* Lc) {
    PolyNode *pa = La->next, *pb = Lb->next, *pc;
    *Lc = (PolyNode*)malloc(sizeof(PolyNode));
    pc = *Lc;
    while (pa != NULL && pb != NULL) {
        if (pa->expn < pb->expn) {
            pc->next = pa;
            pc = pa;
            pa = pa->next;
        } else if (pa->expn > pb->expn) {
            PolyNode* p = (PolyNode*)malloc(sizeof(PolyNode));
            p->coef = -pb->coef;
            p->expn = pb->expn;
            pc->next = p;
            pc = p;
            pb = pb->next;
        } else {
            int diff = pa->coef - pb->coef;
            if (diff != 0) {
                PolyNode* p = (PolyNode*)malloc(sizeof(PolyNode));
                p->coef = diff;
                p->expn = pa->expn;
                pc->next = p;
                pc = p;
            }
            pa = pa->next;
            pb = pb->next;
        }
    }
    while (pa != NULL) {
        pc->next = pa;
        pc = pa;
        pa = pa->next;
    }
    while (pb != NULL) {
        PolyNode* p = (PolyNode*)malloc(sizeof(PolyNode));
        p->coef = -pb->coef;
        p->expn = pb->expn;
        pc->next = p;
        pc = p;
        pb = pb->next;
    }
}

/* 多项式相乘 */
void mulPoly(PolyList La, PolyList Lb, PolyList* Lc) {
    PolyNode *pa = La->next, *pb = Lb->next, *pc = NULL, *temp;
    *Lc = (PolyNode*)malloc(sizeof(PolyNode));
    (*Lc)->next = NULL;
    while (pa != NULL) {
        pb = Lb->next;
        while (pb != NULL) {
            int coef = pa->coef * pb->coef;
            int expn = pa->expn + pb->expn;
            temp = (*Lc)->next;
            pc = *Lc;
            while (temp != NULL && temp->expn > expn) {
                pc = temp;
                temp = temp->next;
            }
            if (temp != NULL && temp->expn == expn) {
                temp->coef += coef;
            } else {
                PolyNode* p = (PolyNode*)malloc(sizeof(PolyNode));
                p->coef = coef;
                p->expn = expn;
                p->next = temp;
                pc->next = p;
            }
            pb = pb->next;
        }
        pa = pa->next;
    }
}

int main() {
    PolyList L1, L2, L3;

    /* 创建多项式 */
    L1 = (PolyNode*)malloc(sizeof(PolyNode));
    L2 = (PolyNode*)malloc(sizeof(PolyNode));
    createPoly(&L1);
    createPoly(&L2);

    /* 输出多项式 */
    printf("多项式 1：");
    printPoly(L1);
    printf("多项式 2：");
    printPoly(L2);

    /* 相加 */
    addPoly(L1, L2, &L3);
    printf("多项式 1 + 多项式 2：");
    printPoly(L3);

    /* 相减 */
    subPoly(L1, L2, &L3);
    printf("多项式 1 - 多项式 2：");
    printPoly(L3);

    /* 相乘 */
    mulPoly(L1, L2, &L3);
    printf("多项式 1 * 多项式 2：");
    printPoly(L3);

    return 0;
}

注：此代码只是一个简单的实现，可能存在一些问题和不足。