看看代码，在添加多项式（列表）时，在运算符重载时我做错了什么？它没有打印出所需的答案。 e.g。
P1：5x ^ 12 + 2x ^ 9 + 4x ^ 7 + 6x ^ 6 + 1x ^ 3
P2：7x ^ 8 + 2x ^ 7 + 8x ^ 6 + 6x ^ 4 + 2x ^ 2 + 3 ^ x + 40
答案：5x ^ 12 + 2x ^ 9 + 7x ^ 8 + 6x ^ 7 + 14x ^ 6 + 6x ^ 4 + 1x ^ 3 + 2x ^ 2 + 3 ^ x + 40
添加它们的正确方法是什么？
#include <stdio.h>
#include <iostream>
using namespace std;
//Node is defined
class node {
public:
//value will contain data
int value1;
int value2;
//next stores location
node *next;
//Default Constructor
node()
{
value1 = 0;
value2 = 0;
next = NULL;
}
};
//mylist is defined
class mylist {
public:
//head will keep notice of beginning of the list
node* head;
//track number of nodes
int count = 0;
//default constructor
mylist() {}
//constructor
//insert at beginning
void insert_at_beginning(int new_value1, int new_value2)
{
//creating new node
node *new_node = new node();
//increasing count
count++;
//copying value to new_node
new_node->value1 = new_value1;
new_node->value2 = new_value2;
//pointing head to new_node when we have empty list
if (head == NULL)
{
head = new_node;
}
//when list isn't empty
else
{
/* new_node->next points where heads points*/
new_node->next = head;
/* Updating head node to point to newly added node*/
head = new_node;
}
}
//inert node or item at Specific Location
void insert_at_loc(int location, double new_val1, double new_val2)
{
//temp node to keep track of location
node* temp = head;
//x acts as counter
int x = count;
//check if location is valid or not
if (count < location) {
cout << ("\n --Invalid Location Node Can't be Added at this Location -- ") << endl;
}
else {
//traversing thourgh list finding specific location to add node
while (x != NULL) {
if (x == (count - location + 2)) {
//found location now creating new node and fixing links
node *new_node1 = new node();
//increasing count
count++;
new_node1->value1 = new_val1;
new_node1->value2 = new_val2;
//new_node1->next points to temp->next
new_node1->next = temp->next;
//temp-next points to newly added new_node1
temp->next = new_node1;
}
else {
temp = temp->next;
}
x--;
}
}
}
//printing list
void printList()
{
cout << endl << "Linked-List : ";
node* temp = head;
while (temp != NULL) {
cout << temp->value2 << "x^" << temp->value1 << "--> ";
temp = temp->next;
}
}
void del(int del_loc) {
//temp1 to keep track location
node* t1 = head;
//if location is head
if (del_loc <= 1) {
head = t1->next;
//free memory
delete(t1);
//decrementing count
count--;
}
//location is other than head
else if (del_loc < count) {
for (int y = count; y != (count - del_loc + 2); y--) {
t1 = t1->next;
}
//fixing links
node* t2 = t1->next;
t1->next = t2->next;
//free memory
delete t2;
//decrementing count
count--;
}
else {
cout << "\n **Sorry Location Doesn't Exist **" << endl;
}
}
//Display Number of Nodes
void count_func() {
cout << "\n\n No. of Nodes Present in Linked List : " << count << endl;
}
void mylist::operator+=(const mylist& l2) {
node *temp_l1 = head;
node *temp_l2 = l2.head;
mylist answer;
while ((temp_l1 != NULL) && (temp_l2 != NULL)) {
if (temp_l1 != NULL && temp_l2 == NULL) {
answer.insert_at_beginning(temp_l1->value1, temp_l1->value2);
temp_l1 = temp_l1->next;
}
if (temp_l1 == NULL && temp_l2 != NULL) {
answer.insert_at_beginning(temp_l2->value1, temp_l2->value2);
temp_l2 = temp_l2->next;
}
if (temp_l1 != NULL && temp_l2 != NULL) {
if (temp_l1->value1 == temp_l2->value1) {
answer.insert_at_beginning(temp_l1->value1, (temp_l1->value2+temp_l2->value2) );
if (temp_l1 != NULL)
temp_l1 = temp_l1->next;
if (temp_l2 != NULL)
temp_l2 = temp_l2->next;
}
else if (temp_l1->value1 > temp_l2->value1 ) {
answer.insert_at_beginning(temp_l1->value1, temp_l1->value2);
temp_l1 = temp_l1->next;
}
else if (temp_l1->value1 < temp_l2->value1) {
answer.insert_at_beginning(temp_l2->value1, temp_l2->value2);
temp_l2 = temp_l2->next;
}
}
}
node *temp_ans = answer.head;
while (temp_ans != NULL) {
cout << temp_ans->value2 << "z^" << temp_ans->value1 << "--> ";
temp_ans = temp_ans->next;
}
}
};
int main() {
//creating linked_list
mylist linked_list;
mylist linked_list_1;
mylist linked_list_2;
mylist linked_list_ans;
int menu = 0;
int list_1_exp = 0;
int list_1_exp_check = -100;
double list_1_coef;
char list_1_menu = 0;
cout << " *********************** Enter 1st Polynomial in Ascending Order w.r.t Exponential *********************** " << endl;
while (list_1_menu != 'E' || list_1_menu != 'e') {
cout << " \nWould you like to add term in 1st Polynomial (y or n): " << endl;
cout << " Enter 'E' to exit: " << endl;
cout << " Your Choice: ";
cin >> list_1_menu;
if (list_1_menu == 'Y' || list_1_menu == 'y') {
cout << "Enter the Exponent for the term : ";
cin >> list_1_exp;
if (list_1_exp > list_1_exp_check || list_1_exp_check == -100) {
list_1_exp_check = list_1_exp;
}
else if (list_1_exp <= list_1_exp_check) {
cout << " Invalid Exponent for the term (can't be Equal or Less than Last Term) " << endl;
cout << " Please Enter Exponent Greater than " << list_1_exp_check << endl;
cout << " Enter the Exponent for the term : ";
cin >> list_1_exp;
list_1_exp_check = list_1_exp;
}
cout << "Enter the Coefficent for the term : ";
cin >> list_1_coef;
linked_list_1.insert_at_beginning(list_1_exp, list_1_coef);
linked_list_1.printList();
cout << " NULL" << endl << endl;
}
else if (list_1_menu == 'N' || list_1_menu == 'n') {
break;
}
else if (list_1_menu == 'E' || list_1_menu == 'e') {
break;
}
}
//priting list
linked_list_1.printList();
cout << " NULL" << endl << endl;
int list_2_exp = 0;
int list_2_exp_check = -100;
double list_2_coef;
char list_2_menu = 0;
cout << " \n *********************** Enter 2nd Polynomial in Ascending Order w.r.t Exponential ***********************" << endl;
while (list_2_menu != 'E' || list_2_menu != 'e') {
cout << " \nWould you like to add term in 2nd Polynomial (y or n): " << endl;
cout << " Enter 'E' to exit: " << endl;
cout << " Your Choice: ";
cin >> list_2_menu;
if (list_2_menu == 'Y' || list_2_menu == 'y') {
cout << "Enter the Exponent for the term : ";
cin >> list_2_exp;
if (list_2_exp > list_2_exp_check || list_2_exp_check == -100) {
list_2_exp_check = list_2_exp;
}
else if (list_2_exp <= list_1_exp_check) {
cout << " Invalid Exponent for the term (can't be Equal or Less than Last Term) " << endl;
cout << " Please Enter Exponent Greater than " << list_2_exp_check << endl;
cout << " Enter the Exponent for the term : ";
cin >> list_2_exp;
list_2_exp_check = list_2_exp;
}
cout << "Enter the Coefficent for the term : ";
cin >> list_2_coef;
linked_list_2.insert_at_beginning(list_2_exp, list_2_coef);
linked_list_2.printList();
cout << " NULL" << endl << endl;
}
else if (list_2_menu == 'N' || list_2_menu == 'n') {
break;
}
else if (list_2_menu == 'E' || list_2_menu == 'e') {
break;
}
}
//priting list
linked_list_2.printList();
cout << " NULL" << endl << endl;
linked_list_1.printList();
cout << " NULL" << endl << endl;
cout << " Addition " << endl;
linked_list_1 += (linked_list_2);
cout << "\nFinal List" << endl;
linked_list_ans.printList();
//program success
system("pause");
return 0;
}
我认为我尝试添加的逻辑是有道理的，但它不起作用。在大多数情况下，如果我在具有相同度数的多项式中具有相等的项，则它起作用。它适用于此但不适用于所有情况。请帮忙！
答案 0 :(得分：1)
为什么不保持简单：
创建map<int, int>。遍历P1和P2，将indices插入key，并将coefficient设为value。如果地图中已存在index或power，则增加条目的值，否则创建索引为key的新条目。在完成P1和P2的遍历之后，地图将组成具有索引作为关键字的条目和P1和P2中每个幂/索引的系数之和作为对应值。
答案 1 :(得分：0)
循环条件(temp_l1 != NULL) && (temp_l2 != NULL)保证temp_l1 != NULL && temp_l2 == NULL和temp_l1 == NULL && temp_l2 != NULL始终为false，因此永远不会执行相应if的主体。将它们从循环中取出（当然，将它们转换为循环）。
PS：要快速找到这样的问题，请使用调试器。