第三周学习总结(长整数算数运算系统)
本周写了长整数的四则运算系统，还练习了图书管理系统连接Hadoop的数据库，代码时间：每天两小时左右，同时学习了python爬虫连接数据库的实例。
下周开始学习python爬虫网络热词的主要知识点。
遇到的问题：
(1)python在连接数据库时出现了报错：
原因因为数据库参数中的数据库名称出现了错误导致无法连接到数据库，通过语句SELECT Name FROM Master…SysDatabases ORDER BY Name 查询到了当前所有数据库的名称，问题得以解决。
(2)
设计一个程序实现两个任意长的整数算数运算，比如加、减、乘等四则运算。
基本要求：
(1) 利用双项循环链表实现长整数的存储，每个结点含一个整型变量。任何整型变量的范围是-（215-1）~（215-1）。输入和输出形式：按中国对于长整数的表示习惯，每四位一组，组间用逗号隔开。
(2) 实现长整数的加法运算；
(3) 实现长整数的减法运算；
(4) 实现长整数的乘法运算；
(5) 实现长整数的除法运算，输出整数商和余数；
(6) 实现长整数的乘方运算等。
实现提示：
① 每个结点中可以存放的最大整数为215-1=32767，才能保证两数相加不会溢出。但若这样存，即相当于按32768进制数存，在十进制数与32768进制数之间的转换十分不方便。故可以在每个结点中仅存十进制数的4位，即不超过9999的非负整数，整个链表视为万进制数。
② 可以利用头结点数据域的符号代表长整数的符号。用其绝对值表示元素结点数目。相加过程中不要破坏两个操作数链表。两操作数的头指针存于指针数组中是简化程序结构的一种方法。不能给长整数位数规定上限。
#include<iostream> #include<string> #include<stdlib.h> using namespace std; #define MAX 1000 typedef struct ListNode{ //结构体，双向循环链表 int data; //结点数据 struct ListNode *pre; //前向指针 struct ListNode *next;//后向指针 }Node, *NodeList; //============================================输入====================================================== //-----------------检查键入字符串格式------------------------- //第一个字符为符号位，其余每一位均在0-9之间或者是逗号,多个分隔符与一个相同 int check(char a[], int m){ if(a[0] == '+' || a[0] == '-'){ for(int i = 1; i < m; i++){ if((int(a[i]) <= 57 && int(a[i]) >= 48) || a[i] == ','){ if(i == m-1) return 1; } else return -1; } } else return -1; } //-------------------------------输入字符串型长整数,去掉分隔符后存入链表中--------------------------------------- void input(NodeList &longint){ longint = new Node; longint -> pre = longint; //初始化结构体变量 longint -> next = longint; int flag1 = 0; int num = 0; int len = 0;//字符串长度 string str; char arr[MAX];//字符数组来存放长整型 cin >> str;//输入一个字符串 len = str.length(); for(int i = 0; i < len; i++){//字符串赋值给字符数组，调用check函数 arr[i] = str[i]; } flag1 = check(arr, len); while(flag1 == -1){//当输入格式不正确时提示，直至输入格式正确 cout << "请重新按照格式输入这个长整数！ " << endl; cin >> str; len = str.length(); for(int i = 0; i < len; i++){ arr[i] = str[i]; } flag1 = check(arr, len); }//while if(arr[0] == '+'){ longint->data = int('+');//字符'+'存储为整型43 } if(arr[0] == '-'){ longint->data = int('-');//字符'-'存储为整型45 } NodeList prenode = longint; for(int i = 1; i < len; i++){//将字符串中每一位使用循环列表存放 if(arr[i] != ','){ num = arr[i] - 48;//字符型转换为整型 NodeList newn = new Node; newn -> data = num; newn -> pre = prenode; newn -> next = longint; prenode -> next = newn; longint -> pre = newn; prenode = newn; } } //一些异常输入处理 if(longint ->next == longint){//当输入的为"+,,,,,,"这种形式时，在链表中存储"+0" NodeList newn = new Node; newn -> data = 0; newn -> pre = longint; newn -> next = longint; longint -> next = newn; longint -> pre = newn; } NodeList nextnode = longint ->next; NodeList oldn;//删除表开头结点的0，如（+0,0001转换为+1保存）；若链表值为0时,保存0（如+0,0000保存为+0） while(nextnode->data == 0 && nextnode->next != longint){ oldn = nextnode; nextnode = nextnode->next; longint ->next = nextnode; nextnode ->pre = longint; delete(oldn); } } //==========================================预处理============================================== //------------------参数为链表，返回链表(数据部分)长度-------------------------- int length(NodeList longint){ int sum = 0; NodeList p = longint->next; while(p != longint){ sum++; p = p->next; } return sum; } //---------------------比较两个链表绝对值大小------------------------------------ //当第一参数大比第二参数绝对值大时返回1，第一参数比第二参数绝对值小时返回-1，否则返回0 int compare(NodeList &longint1, NodeList &longint2){ NodeList p1, p2; p1 = longint1; p2 = longint2; while(p1->next != longint1 && p2->next != longint2){ p1 = p1->next; p2 = p2->next; } if(p1->next != longint1)//第一个链表长，则它的绝对值大 return 1; else if(p2->next != longint2)//第二个链表长，则它的绝对值大 return -1; else{//两个链表一样长时，比较两个链表结点存放数据大小判断 p1 = longint1->next; p2 = longint2->next; while(p1->data == p2->data && p1->next != longint1){ p1 = p1->next; p2 = p2->next; } if(p1->data > p2->data) return 1; else if(p1->data < p2->data) return -1; else return 0; } } //析构，释放链表空间 void removen(NodeList &longint){ NodeList oldn = longint; NodeList nextnode = longint ->next; while(nextnode != longint){ oldn = nextnode; nextnode = nextnode->next; longint ->next = nextnode; nextnode ->pre = longint; delete(oldn); } delete(longint); } //============================================输出-=========================================== //-----------------------将链表中的结果加上分隔符','后输出；------------------------------ //特别地，当结果为0（+0或-0）时直接输出0即可 void output(NodeList &longint){ NodeList p; int num = 0; int sum = length(longint); int n = sum % 4; p = longint->next; if(p->next == longint && p->data == 0){//当计算结果为0（+0或-0）时输出0 cout << "计算结果为: " << 0 << endl; }else{ if(longint -> data == 43)//先输出首部符号 cout << "计算结果为: " << '+'; else if(longint -> data == 45) cout << "计算结果为: " << '-'; while(p != longint){//以4为为一组用分隔符分隔,如 （+1,0000,0000,11） if((num == n || (num - n) % 4 == 0) && num != sum && num!=0) cout << ','; cout << p->data; p = p->next; num++; } } cout << endl; } //============================================加减乘运算=============================================== //-------------基本加法操作------------------ void same_add(NodeList &longint1, NodeList &longint2, NodeList &result){ int carry = 0;//进位 int newdata = 0; NodeList p1, p2, newn; p1 = longint1->pre; p2 = longint2->pre; NodeList nextnode = result; while(p1 != longint1 && p2 != longint2){//从两长整数最后开始逐位进行加法运算 newdata = (p1->data + p2->data + carry); carry = newdata/10; newn = new Node(); if(carry) newn->data = (newdata - 10); else newn->data = newdata; newn->pre = result; newn->next = nextnode; result->next = newn; nextnode->pre = newn; nextnode = newn; p1 = p1->pre; p2 = p2->pre; } while(p1 != longint1){//当p1前部分还有数据时 newdata = (p1->data + carry); carry = newdata/10; newn = new Node(); if(carry) newn->data = (newdata - 10); else newn->data = newdata; newn->pre = result; newn->next = nextnode; result->next = newn; nextnode->pre = newn; nextnode = newn; p1 = p1->pre; } while(p2 != longint2){//当p2前部分还有数据时 newdata = (p2->data + carry); carry = newdata/10; newn = new Node(); if(carry) newn->data = (newdata - 10); else newn->data = newdata ; newn->pre = result; newn->next = nextnode; result->next = newn; nextnode->pre = newn; nextnode = newn; p2 = p2->pre; } if(carry != 0){//计算后，进位不为0时处理 newn = new Node(); newn->data = carry; newn->pre = result; newn->next = nextnode; result->next = newn; nextnode->pre = newn; } //output(result); } //-------------基本减法操作------------------ void same_sub(NodeList &longint1, NodeList &longint2, NodeList &result){ int borrow = 0;//借位 int newdata = 0; NodeList p1, p2, newn; p1 = longint1->pre; p2 = longint2->pre; NodeList nextnode = result; while(p1 != longint1 && p2 != longint2){//从两长整数最后开始逐位进行减法运算 if(p1->data - p2->data - borrow >= 0){//没有借位产生时 newdata = p1->data - p2->data - borrow; borrow = 0; } else{//有借位产生 newdata = (p1->data - p2->data - borrow + 10); borrow = 1; } newn = new Node(); newn->data = newdata; newn->pre = result; newn->next = nextnode; result->next = newn; nextnode->pre = newn; nextnode = newn; p1 = p1->pre; p2 = p2->pre; }//while while(p1 != longint1){//当p1较长时，前部分还有数据 if(borrow){//如果有借位 if(p1->data - borrow >= 0){ newdata = p1->data - borrow; borrow = 0; } else{ newdata = (p1->data - borrow + 10); borrow = 1; } } else//没有借位 newdata = p1->data; newn = new Node(); newn->data = newdata; newn->pre = result; newn->next = nextnode; result->next = newn; nextnode->pre = newn; nextnode = newn; p1 = p1->pre; }//while nextnode = result ->next; NodeList oldn; while(nextnode->data == 0 && nextnode->next != result){//删除表开头结点的0，如（+0001转换为+1）；若链表值为0时，result为（+或-）0 oldn = nextnode; nextnode = nextnode->next; result ->next = nextnode; nextnode ->pre = result; delete(oldn); } //output(result); } //---------------------有符号加法操作-------------------------------------- void add(NodeList &longint1, NodeList &longint2, NodeList &result){ result = new Node;//存放结果,初始化 result ->next = result; result ->pre = result; if(longint1->data == longint2->data){//大整数L1、L2符号相同 if(longint1->data == 43)//L1、L2都是正数，结果为+（L1+L2） result->data = 43; if(longint1->data == 45)//L1、L2都是负数，结果为-（L1+L2） result->data = 45; same_add(longint1, longint2, result); } else{//L1、L2符号相反 if(longint1->data == 43 && longint2->data == 45){//L1符号为正、L2符号为负 if(compare(longint1, longint2) == 1){//L1的绝对值大于L2的绝对值，相当于+（L1-L2） result->data = 43; same_sub(longint1, longint2, result); }else if(compare(longint1, longint2) == -1){//L1的绝对值小于L2的绝对值，相当于-（L2-L1） result->data = 45; same_sub(longint2, longint1, result); }else{//L1的绝对值等于L2的绝对值,输出结果为0 NodeList newn = new Node; newn -> data = 0; newn -> pre = result; newn -> next = result; result -> next = newn; result -> pre = newn; //output(result); } } if(longint1->data == 45 && longint2->data == 43){//L1符号为负、L2符号为正 if(compare(longint1, longint2) == 1){//L1的绝对值大于L2的绝对值，相当于-（L1-L2） result->data = 45; same_sub(longint1, longint2, result); }else if(compare(longint1, longint2) == -1){//L1的绝对值小于L2的绝对值，相当于+（L2-L1） result->data = 43; same_sub(longint2, longint1, result); }else{//L1的绝对值等于L2的绝对值,输出结果为0 NodeList newn = new Node; newn -> data = 0; newn -> pre = result; newn -> next = result; result -> next = newn; result -> pre = newn; //output(result); } } }//else } //------------------有符号减法操作------------------------------- void sub(NodeList &longint1, NodeList &longint2, NodeList &result){ result = new Node;//存放结果,初始化 result ->next = result; result ->pre = result; if(longint1->data == longint2->data){//大整数L1、L2符号相同 if(longint1->data == 43){//L1、L2都是正数 if(compare(longint1, longint2) == 1){//L1的绝对值大于L2的绝对值，相当于+(L1-L2) result->data = 43; same_sub(longint1, longint2, result); }else if(compare(longint1, longint2) == -1){//L1的绝对值小于L2的绝对值，相当于-（L2-L1） result->data = 45; same_sub(longint2, longint1, result); }else{//L1的绝对值等于L2的绝对值,输出结果为0 NodeList newn = new Node; newn -> data = 0; newn -> pre = result; newn -> next = result; result -> next = newn; result -> pre = newn; //output(result); } } if(longint1->data == 45){//L1、L2都是负数 if(compare(longint1, longint2) == 1){//L1的绝对值大于L2的绝对值，相当于-（L1-L2） result->data = 45; same_sub(longint1, longint2, result); }else if(compare(longint1, longint2) == -1){//L1的绝对值小于L2的绝对值，相当于+（L2-L1） result->data = 43; same_sub(longint2, longint1, result); }else{//L1的绝对值等于L2的绝对值,输出结果为0 NodeList newn = new Node; newn -> data = 0; newn -> pre = result; newn -> next = result; result -> next = newn; result -> pre = newn; //output(result); } } } else{//L1、L2符号相反 if(longint1->data == 43)//L1符号为正、L2符号为负 result->data = 43; if(longint1->data == 45)//L1符号为负、L2符号为正 result->data = 45; same_add(longint1, longint2, result); } } //----------------------乘法操作---------------------------------------- void multiply(NodeList &longint1, NodeList &longint2, NodeList &result){ int num = 0; int c = 0; NodeList p1, p2, opr1, opr2; int carry = 0, newdata = 0; result = new Node;//存放结果,初始化 result ->next = result; result ->pre = result; p1 = longint1->next; p2 = longint2->next; if((p1 ->data == 0 && p1 ->next == longint1) || (p2 ->data == 0 && p2 ->next == longint2)){//当两个大整数中有一个为0时结果为0 result -> data = 43;//为结果符号位赋初值（+或-均可）结果为0时不输出符号位 NodeList newn = new Node; newn -> data = 0; newn -> pre = result; newn -> next = result; result -> next = newn; result -> pre = newn; }//if else{ if(longint1->data == longint2->data)//大整数L1、L2符号相同,结果符号为'+' result ->data = 43; else//大整数L1、L2符号不同，结果符号为'—' result ->data = 45; if(compare(longint1, longint2) == -1){//使绝对值较大的作为操作数1，进行计算 opr1 = longint2; opr2 = longint1; }else{ opr1 = longint1; opr2 = longint2; } NodeList pp2 = new Node;//构造一个pp2链表，内容为（+0），后面进行更新求和 pp2 -> data = 43;//任意 pp2 -> pre = pp2; pp2 -> next = pp2; NodeList newn = new Node; newn -> data = 0; newn -> pre = pp2; newn -> next = pp2; pp2 -> next = newn; pp2 -> pre = newn; NodeList pp1 = new Node;//链表pp1 pp1 -> data = 43;//任意 pp1 -> pre = pp1; pp1 -> next = pp1; NodeList po1, po2; po1 = opr1 ->pre; po2 = opr2 ->pre; while(po2 != opr2){ carry = 0; po1 = opr1 ->pre; NodeList nextnode = pp1; while(po1 != opr1){//将po2链表中数据，逐个与po1中数据计算相乘，存入链表pp1中 if((po1 ->data * po2 ->data + carry) < 10){ newdata = (po1 ->data) * (po2 ->data) + carry; carry = 0; } else{ newdata = (po1 ->data * po2 ->data + carry) % 10; carry = (po1 ->data * po2 ->data + carry) / 10; } NodeList newnode = new Node; newnode->data = newdata; newnode->pre = pp1; newnode->next = nextnode; pp1->next = newnode; nextnode->pre = newnode; nextnode = newnode; po1 = po1 ->pre; } if(carry != 0){//计算后，进位不为0时处理 newn = new Node(); newn->data = carry; newn->pre = pp1; newn->next = nextnode; pp1->next = newn; nextnode->pre = newn; } c = num; while(c != 0){//从第二次循环开始每次向左移一位，相当于每个pp1乘以pow(10, num) NodeList zero = new Node; NodeList pnode ; pnode = pp1 ->pre; zero -> data = 0; zero -> pre = pnode; zero -> next = pp1; pnode -> next = zero; pp1 -> pre = zero; c--; } same_add(pp2, pp1, result); //output(result); //将result的值赋值给pp2进行运算; //clearlist(pp2); pp2 ->data = result ->data; NodeList nextr = result ->next; NodeList prenode = pp2; while(nextr != result){ NodeList newnode = new Node; newnode->data = nextr ->data; newnode->pre = prenode; newnode->next = pp2; prenode->next = newnode; pp2 ->pre = newnode; prenode = newnode; nextr = nextr ->next; } num++; po2 = po2 ->pre; } }//else //output(result); } //=======================================主调函数部分========================================== //------------------------打印欢迎界面--------------------------------- void welcome(){ cout << "********************************************************************" << endl; cout << "* 任意长整数的加减乘法运算 *" << endl; cout << "********************************************************************" << endl; cout << "基本操作要求：" << endl; cout << "1.输入格式每四组一位，组间用逗号隔开。" << endl; cout << "2.输入的长整数必须带有符号（+或-）,如：+1,0000,000。" << endl; cout << "3.组间多个分隔符看做一个(如：+1,,,1000 相当于 +1,1000)。" << endl; cout << "********************************************************************" << endl; cout << endl; } //---------------------------打印操作界面----------------------------------- void print(){ cout << " ************************************************" << endl; cout << " ************************************************" << endl; cout << " 输入1、2、3、4选择操作 " << endl; cout << " 1、加法 " << endl; cout << " 2、减法 " << endl; cout << " 3、乘法 " << endl; cout << " 4、退出 " << endl; cout << " ************************************************" << endl; cout << " ************************************************" << endl; cout << endl; } //------------------------------主处理函数------------------------------ void handle_do(){ char op; NodeList longint1, longint2, longresult; //输入两个操作数 cout << "请输入第一个带符号的操作数(如-1,0000,0001或+1,0000,0001): " << endl; input(longint1); cout << "请输入第二个带符号的操作数(如-1,0000,0001或+1,0000,0001): " << endl; input(longint2); print();//打印操作界面 cout << "请输入你的选择: " << endl; cin >> op; while(op > '4' || op < '1'){//当输入选择符号错误时，提示输入正确的选择 cout << "请输入正确的选择： " << endl; cin >> op; } switch(op){//根据选择，匹配执行对应操作 case '1': add(longint1, longint2, longresult); output(longresult); break; case '2': sub(longint1, longint2, longresult); output(longresult); break; case '3': multiply(longint1, longint2, longresult); output(longresult); break; case '4': exit(0);//退出系统 } removen(longint1); removen(longint2); removen(longresult); } //-------------------------主函数---------------------------------- int main() { char ch; int flag = 1; welcome(); //打印欢迎界面 while(flag){//标志有效时，可以持续执行 handle_do();//调用主处理函数- cout << endl; cout << "是否继续？是(y)，否(n): " ; cin >> ch; cout << endl; while(ch != 'y' && ch != 'n'){//当键入无效字符时提醒，直至输入有效字符 cout << "请输入正确选择！是(y)，否(n): " ; cin >> ch; cout << endl; } if(ch == 'n'){ flag = 0; } } return 0; }
