多项式乘法比较复杂，先实现多项式的加法，可以大大化简程序，输入输出采用文件的形式。
代码如下：
#include <iostream>#include <fstream>using namespace std;typedef struct PNode{double c;int e;struct PNode *next;}PNode, *PolyList;//创建一个空结点void CreateNode(PolyList &p){p = new PNode;}//打开文件并读取信息void OpenFile(double cArray[], int eArray[], int &count){ifstream ifs;ifs.open("poly1.txt", ios::out);if (!ifs.is_open()){cout << "文件打开失败！" << endl;}char ch;double c;int e;count = 0;while (ifs >> c && ifs >> ch && ifs >> e){cArray[count] = c;eArray[count] = e;count++;}}//将多项式的信息保存到文件中void SaveFile(PolyList &L){PolyList p;p = L->next;int count = 0;double cArray[99] = { 0 };int eArray[99] = { 0 };//读取链表中的数据while (p){cArray[count] = p->c;eArray[count] = p->e;p = p->next;count++;}//保存到文件ofstream ofs;ofs.open("poly3.txt", ios::out);if (!ofs.is_open()){cout << "文件打开失败！" << endl;}for (int i = 0; i < count; i++){ofs << cArray[i] << "," << eArray[i] << " ";}}//创建单链表void CreateList(PolyList &L, int e[], double c[], int n){PolyList p, q;CreateNode(L); //创建头结点q = L;//尾插法for (int i = 0; i < n; i++){CreateNode(p);p->c = c[i];p->e = e[i];q->next = p;q = p;}q->next = NULL;}//遍历链表void Traverse(PolyList &L){PolyList p;p = L->next;while (p){cout << p->c << " ";p = p->next;}cout << endl;}//实现两个链表的相加PolyList add(PolyList &ha, PolyList &hb){PolyList p, pa, pb, pc, hc;pa = ha->next;pb = hb->next;CreateNode(hc);pc = hc;while (pa && pb){if (pa->e < pb->e){p = pa;pa = pa->next;}else if (pa->e > pb->e){p = pb;pb = pb->next;}else {pa->c += pb->c;if (pa->c == 0){p = pa; pa = pa->next; delete p;p = pb; pb = pb->next; delete p;continue;}p = pb; pb = pb->next; delete p;p = pa; pa = pa->next;}pc->next = p; pc = p;}if (pa) pc->next = pa;else if (pb) pc->next = pb;else pc->next = NULL;return hc;}//实现两个链表的相乘PolyList muti(PolyList &hp, PolyList &hq){PolyList p, q, hr, ht, pt;CreateNode(hr); hr->next = NULL;CreateNode(ht); ht->next = NULL;q = hq->next;while (q){pt = ht;p = hp->next;while (p){CreateNode(pt->next); pt = pt->next;pt->c = q->c * p->c;pt->e = q->e + p->c;p = p->next;}pt->next = NULL;q = q->next;p = add(ht, hr);delete hr;hr = p;}delete ht;return hr;}int main(){double c1[10], c2[10] = {0};int e1[10], e2[10] = {0};int count1, count2;OpenFile(c1, e1, count1);OpenFile(c2, e2, count2);PolyList L1, L2, L3;CreateList(L1, e1, c1, count1);Traverse(L1);CreateList(L2, e2, c2, count2);Traverse(L2);L3 = muti(L1, L2);Traverse(L3);SaveFile(L3);}