c++课程作业单链表单链表

#include <string> #include <iostream> #include <cassert> using namespace std; typedef struct NODE node; typedef struct NODE* nodeptr; typedef string::size_type size_type; struct NODE { nodeptr link; int value; }; class List { private: nodeptr head; nodeptr tail; int charToInt(char ch) { return ((int)ch - 48); } public: List(); void create(string& str); void insertBack(int value); void reverse(); List& operator+(List& list); void show(); }; //构造函数，默认构造一个只有头结点的链表 List::List() { head = (nodeptr)operator new(sizeof(node)); assert(head != NULL); head->link = NULL; head->value = 0; tail = NULL; } //根据传入的大数字符串创建一个相对应的链表 void List::create(string& str) { for (size_type i = 0; i < str.size(); ++i) { insertBack(charToInt(str[i])); } } //每次都在链表的后面插入 void List::insertBack(int value) { if (tail == NULL) { head->value = value; tail = head; return; } nodeptr newNode = (nodeptr)operator new(sizeof(node)); assert(tail != NULL); assert(newNode != NULL); newNode->link = tail->link; tail->link = newNode; newNode->value = value; tail = newNode; } //用三个指针实现单链表的逆序，这是面试真题 void List::reverse() { nodeptr curr = head; nodeptr pre = NULL; nodeptr next; while (curr != NULL) { next = curr->link; curr->link = pre; pre = curr; curr = next; } head = pre; } //重载+运算符 //单链表实现大数运算最主要的函数 List& List :: operator+(List& list) { List *list3 = new List(); int bitAdd = 0; int jinWei = 0; this->reverse(); list.reverse(); nodeptr pList1 = this->head; nodeptr pList2 = list.head; while (pList1 != NULL || pList2 != NULL) { if (pList1 != NULL && pList2 != NULL) { bitAdd = pList1->value + pList2->value + jinWei; jinWei = bitAdd / 10; bitAdd = bitAdd % 10; pList1 = pList1->link; pList2 = pList2->link; } else if (pList1 == NULL) { bitAdd = pList2->value; jinWei = 0; pList2 = pList2->link; } else { bitAdd = pList1->value; jinWei = 0; pList1 = pList1->link; } list3->insertBack(bitAdd); } if (jinWei != 0) list3->insertBack(jinWei); list3->reverse(); return *list3; } //屏幕上打印出链表 void List::show() { nodeptr it = head; while (it != NULL) { cout << it->value; it = it->link; } cout << endl; } int main() { string str1; string str2; cout << "please input the number1: "; cin >> str1; cout << "please input the number2: "; cin >> str2; List bigNum1; List bigNum2; List result; bigNum1.create(str1); bigNum2.create(str2); result = bigNum1 + bigNum2; cout << "result : " << endl; result.show(); return 0; }