一元多项式加法乘法运算C+链表

//#include<stdio.h> //#include<stdlib.h> #include"stdafx.h" #include<malloc.h> #include<Windows.h> //#define ERROR 0; //#define OVERFLOW 0; typedef struct Polyn { int expn, coef; Polyn* next; }*P; P CreatePolyn(Polyn *P); // 创建节点 Polyn* SelectSort(Polyn *Pa); // 选择排序 Polyn* MergePolyn(Polyn *Pa); //合并同类项 void PrintPolyn(Polyn *P); // 打印多项式 int cmp(int a, int b); // 比较函数 P AddPolyn(P Pa, P Pb); // 多项式相加 P MultiPolyn(P Pa, P Pb); // 多项式相乘 /*------------------------Dome---------------------------------*/ int main() { P Pa, Pb, Pc, Pd; Pa = (Polyn *)malloc(sizeof(Polyn)); Pb = (Polyn *)malloc(sizeof(Polyn)); Pa = CreatePolyn(Pa); Pb = CreatePolyn(Pb); Pd = MultiPolyn(Pa, Pb); Pc = AddPolyn(Pa, Pb); system("pause"); return 0; } /*-----------------------打印多项式------------------------------*/ void PrintPolyn(Polyn* P) { Polyn* q = P->next; //若多项式为空 printf("\n"); while (q->next != NULL) { if (q->coef>0) printf("%d*x^%d+", q->coef, q->expn); else if (q->coef < 0) { printf("(%d)*x^%d+", q->coef, q->expn); } else printf(""); q = q->next; } if (q->coef>0) printf("%d*x^%d", q->coef, q->expn); else printf("(%d)*x^%d", q->coef, q->expn); } /*-----------------------合并同类项------------------------------*/ Polyn* MergePolyn(Polyn *Pa) { P p, pBefore, del; pBefore = Pa->next; p = pBefore->next; while (p) { if (p->expn == pBefore->expn) { del = p; pBefore->coef = pBefore->coef + p->coef; p = p->next; pBefore->next = p; free(del); } else pBefore = p; p = p->next; } //PrintPolyn(Pa); return Pa; } /*-----------------------创建节点--------------------------------*/ P CreatePolyn(Polyn *P) { Polyn *previous, *current, *head; head = (Polyn *)malloc(sizeof(Polyn)); if (!head) exit(0); head->coef = 0; head->expn = -1; head->next = NULL; previous = head; int coef, expn; printf("\n请输入系数和指数（输入为(0,0)时结束）:\n"); scanf_s("%d%d", &coef, &expn); for (; (coef != 0) || (expn != 0);) { if (coef != 0) { current = (Polyn *)malloc(sizeof(Polyn)); current->coef = coef; current->expn = expn; current->next = NULL; previous->next = current; previous = current; current = previous->next; scanf_s("%d%d", &coef, &expn); } else scanf_s("%d%d", &coef, &expn); } P = SelectSort(head); P = MergePolyn(head); PrintPolyn(P); return P; } /*------------------------选择排序-------------------------------*/ Polyn* SelectSort(Polyn *head) { Polyn *pfirst = NULL; //有序链表表头指针 Polyn *ptail = NULL; //有序链表表尾指针 Polyn *pmin = NULL; //存储最小节点 Polyn *pminBefore = NULL; //存储最小节点的前驱节点 Polyn *p = NULL; //当前比较节点 //pfirst = NULL; while (head != NULL) /*在链表中找键值最小的节点。*/ { /* 注意：这里for语句就是体现选择排序思想的地方 */ for (p = head, pmin = head; p->next != NULL; p = p->next) /*循环遍历链表中的节点，找出此时最小的节点。*/ { if (p->next->expn < pmin->expn) /*找到一个比当前min小的节点。*/ { pminBefore = p; /*保存找到节点的前驱节点：显然p->next的前驱节点是p。*/ pmin = p->next; /*保存键值更小的节点。*/ } } /*上面for语句结束后，就要做两件事；一是把它放入有序链表中；二是根据相应的条件判断，安排它离开原来的链表。 第一件事*/ if (pfirst == NULL) /* 如果有序链表目前还是一个空链表 */ { pfirst = pmin; /* 第一次找到键值最小的节点。 */ ptail = pmin; /* 注意：尾指针让它指向最后的一个节点。 */ } else /* 有序链表中已经有节点 */ { ptail->next = pmin; /* 把刚找到的最小节点放到最后，即让尾指针的next指向它。*/ ptail = pmin; /* 尾指针也要指向它。 */ } /*第二件事*/ if (pmin == head) /* 如果找到的最小节点就是第一个节点 */ { head = head->next; /* 显然让head指向原head->next,即第二个节点，就OK */ } else /*如果不是第一个节点*/ { pminBefore->next = pmin->next; /*前次最小节点的next指向当前pmin的next,这样就让pmin离开了原�