基于动态链表的“大整数加法运算器”

代码写得比较菜>_<

#include<iostream> //基于动态链表的“大整数加法运算器”
#include<cstring>
#define N 100
using namespace std;
struct node
{
	int x;
	node *next;
};
node *head_a = NULL;  
node *tail_a = NULL;
node *head_b = NULL; 
node *tail_b = NULL;
int len_a=0, len_b=0, index=0;  //index是记录答案长度最大下标
char *a = new char[N];
char *b = new char[N];
int *s = new int[N];  //储存答案

node *createnode(int i,char *s) 
{
	node *temp = new node;
	temp->x = s[i] - '0';
	temp->next = NULL;
	return temp;
}
void createlist(int i, node** head, node** tail, char *s) 
{
	while(i >= 0)
	{
		node *temp = createnode(i,s);
		if(*head == NULL)  
		{
			*head = temp;
		}
		else
		{
			(*tail)->next = temp;  
		}
		*tail = temp;
		i--;
	}
}
void add() //主要实现
{
	int n=0;
	node *p1=head_a, *p2=head_b;
	while(p1->next!=0 && p2->next!=0) //只算到最大相等位数那一位
	{
		s[n] = p1->x + p2->x;
		n++;
		p1 = p1->next;
		p2 = p2->next;
	}
	s[n] = p1->x + p2->x;  //这里指向相等的那一位数
	if(p1->next!=0 && p2->next==0)  //如果p1还有下一位
	{
		n++;
		p1 = p1->next;
		index = len_a-1;  //可以确定答案的长度了
		while(1)  //把剩下的都赋值给s
		{
			s[n] = p1->x;
			if(p1->next==0) break;   //如果是最后一位停止
			n++;
			p1 = p1->next;
		}
	}
	if(p1->next==0 && p2->next!=0)  //如果p2还有下一位
	{
		n++;
		p2=p2->next;
		index=len_b-1;
		while(1)  //把剩下的都赋值给s
		{
			s[n] = p2->x;
			if(p2->next==0) break;
			n++;
			p2 = p2->next;
		}
	}
	int k=0;
	while(1)
	{
		if(index==0)  break;
		if(s[k] >= 10)  //除了最后一个大于9的数不用管，把其他大于9的进位
		{
			s[k] -= 10;
			s[k+1]++;
		}
		k++;
		if(k == index) break;
	}
}
void deletelist(node *p)
{
	node *w=p,*v=NULL;
	while(w)
	{
		v = w;
		w = w->next;
		delete v;
	}
}
int main()
{
	cin >> a >> b; 
	len_a = strlen(a);
	len_b = strlen(b);
	node** head1 = &head_a;
	node** tail1 = &tail_a; 
	node** head2 = &head_b; 
	node** tail2 = &tail_b; 
	createlist(len_a-1,head1,tail1,a);
	createlist(len_b-1,head2,tail2,b);
	index = len_a-1;  //(最大下标肯定是大数的位数，先默认为 a的长度)
	add();
	cout << a << " + " << b << " = ";
	for(int i=index; i>=0; i--)
		cout << s[i];
	deletelist(head_a);
	deletelist(head_b);
	delete []a;
	delete []b;
	delete []s;
	return 0;
}