逆波兰计算器加强版：多项式

不说了不说了，，，

链表感觉白学了（学了吗？）= =

鲍鱼鲍鱼。。。。哇哇哇

http://paste.ubuntu.com/15464514/

//cww  多项式计算器
#include<stack>
#include<cstdio>
#include<iostream>
using namespace std;

struct term{
int degree;
double coefficient;
term *next;
term (){coefficient=0;degree=0;next=NULL;}
};

void append(term *head,double cft,int dge){//尾插
term *nw=new term;//只有new没有free= =
nw->coefficient=cft;//用完请重启 23333
nw->degree=dge;
term *q=head;
while (q->next!=NULL){q=q->next;}
q->next=nw;
}
//===============================================
void print(term *head){
term *p=head->next;
bool first=1;
for(;p!=NULL;p=p->next){
if (first){first=0;if (p->coefficient<0)printf("-");}//符号
else if (p->coefficient<0)printf("-");
else printf("+");
double r=(p->coefficient>=0)?p->coefficient:-(p->coefficient);
if (r!=1)printf("%.0lf",r);
if (p->degree>1)printf("X^%d",p->degree);
if (p->degree==1)printf("X");
if (r==1&&p->degree==0)printf("1");
}
if (first)printf("0");//空
puts("");
}
//===============================================
term *Plus(term *p,term *q){
p=p->next;q=q->next;
term *ans=new term;

while (p!=NULL||q!=NULL){
if (p==NULL){//比书上多了个判断NULL。。。
append(ans,q->coefficient,q->degree);
q=q->next;
}else if (q==NULL){
append(ans,p->coefficient,p->degree);
p=p->next;
}else if (p->degree > q->degree){
append(ans,p->coefficient,p->degree);
p=p->next;
}else if (p==NULL||p->degree < q->degree){
append(ans,q->coefficient,q->degree);
q=q->next;
}else {
double cft=p->coefficient+q->coefficient;
term *nw=new term;
if (cft)append(ans,cft,p->degree);
p=p->next;q=q->next;
}
}
return ans;
}

term *Minus(term *p,term *q){
p=p->next;q=q->next;
term *ans=new term;
while (p!=NULL||q!=NULL){
if (p==NULL){//同上同上
append(ans,q->coefficient,q->degree);
q=q->next;
}else if (q==NULL){
append(ans,p->coefficient,p->degree);
p=p->next;
}else if (p->degree > q->degree){
append(ans,p->coefficient,p->degree);
p=p->next;
}else if (p->degree < q->degree){
append(ans,-q->coefficient,q->degree);
q=q->next;
}else {
double cft=p->coefficient-q->coefficient;
term *nw=new term;
if (cft)append(ans,cft,p->degree);
p=p->next;q=q->next;
}
}
return ans;
}

term *mul(term *head,double cft,int dge){
term *p=head->next;
for (;p!=NULL;){//单项乘多项
p->coefficient=p->coefficient*cft;
p->degree=p->degree+dge;
p=p->next;
}
return head;
}

term *Copy(term *p){//复制一个多项式。。。。
term *head=new term;
for (p=p->next;p!=NULL;p=p->next){
append(head,p->coefficient,p->degree);
}
return head;
}

term *mult (term *p,term *q){//乘法
term *ans=new term;
term *qq=Copy(q);
for (p=p->next;p!=NULL;p=p->next){
term *tmp=mul(qq,p->coefficient,p->degree);
qq=Copy(q);//乘完之后，q你变了- -
ans=Plus(ans,tmp);
}
return ans;
}
//**********************************************
//有个print在上面
//如果你的输入不合法，，，嘿嘿嘿
term *read(){//读入多项式
term *head=new term;
puts("Give me a polynoimal:");
double cft;//coefficient
int dge;   //degree
printf("Enter a coeffficient(end with 0):");
scanf("%lf",&cft);
for (;cft!=0;){
printf("Enter a degree:");
scanf("%d",&dge);
append(head,cft,dge);
printf("Enter a coeffficient(end with 0):");
scanf("%lf",&cft);
}
return head;
}
//==============我是分割线====================
stack<term*>s;

char getorder(){//获取指令
while (1){
printf("Select command and press<Enter>:");
char ch; cin>>ch;
if (ch=='?'||ch=='='||ch=='+'||
ch=='-'||ch=='*'||ch=='/'||
ch=='q'||ch=='Q')return ch;
puts("Please enter a valid command:");
puts("[?]push to stack [=]print top");
puts("[+] [-] [*] [/] you know them");
puts("[Q]uit =======Bazinga!=======");
}
}

bool solve(char ch){//逆波兰计算器主进程
term *x,*y;
if (ch=='q'||ch=='Q'){puts("88");return 0;}
if (ch=='?'){s.push(read());}
if (ch=='='){
if (s.empty())puts("Stack empty");
else {term *top=s.top();print(top);}
}
if (ch=='+'||ch=='-'||ch=='*'){
if (s.empty())puts("Stack empty");
else{
x=s.top(); s.pop();
if (s.empty()){
puts("Stack has just one entry");
s.push(x);
}else{
y=s.top();s.pop();
switch (ch){
case'+':s.push(Plus(x,y));break;
case'-':s.push(Minus(x,y));break;
case'*':s.push(mult(x,y));break;
}
}
}
}
return 1;
}
//==========cww=2016=3=21=23:57============
int main(){
//freopen("fuck.in","r",stdin);
//freopen("fuck.out","w",stdout);
puts("welcome");
while (!s.empty())s.pop();
while (solve(getorder())){}
return 0;
}

再次感谢静静（鲁迅）的语法指导

其实自己写傻了

根本不用链表

直接来个栈套栈就好了。。。

谁让鲍鱼要求了呢T_T

就当链表练习把。。。。class还是不会写。。。。呜呜呜