링크드리스트, 계산기 구현

calculator.cpp

+#include <iostream>
+#include <stack>
+#include <cstdlib>
+
+class Calculator{
+public:
+    std::string infix_to_postfix(std::string&  infix);
+    int run_calculate(std::string& input);
+};
+
+std::string Calculator::infix_to_postfix(std::string& infix){
+    std::stack<std::string> sign;
+    std::string postfix;
+    if(infix[0] == '+' || infix[0] == '-'){
+        std::cout << "parse error";
+        return "err";
+    }
+    for(int i = 0; i < infix.size(); i++){
+        if(infix[i] == ' '){
+            continue;
+        }
+
+        if(infix[i] == '('){
+            sign.push(std::string(1, infix[i]));
+        }else if(infix[i] >= '0' && infix[i] <= '9'){
+            postfix = postfix + infix[i];
+            if(infix[i+1] != '\0' && infix[i+1] >= '0' && infix[i+1] <= '9'){
+                continue;
+            }else{
+                postfix = postfix + " ";
+            }
+        }else if(infix[i] == ')'){
+            if(sign.empty()){
+                std::cout << "parse error";
+                return "err";
+            }
+            while(sign.top() != "("){
+                if(sign.empty()){
+                    std::cout << "parse error";
+                    return "err";
+                }
+                postfix = postfix + sign.top() + " ";
+                sign.pop();
+            }
+            sign.pop();
+        }else{  // infix[i] == '+' || infix[i] == '-' || infix[i] == '*' || infix[i] == '/'
+            if(sign.empty()){
+                sign.push(std::string(1, infix[i]));
+                continue;
+            }
+            if(infix[i] == '*' || infix[i] == '/'){
+                if(sign.top() == "*" || sign.top() == "/"){
+                    postfix = postfix + sign.top() + " ";
+                    sign.pop();
+                    sign.push(std::string(1, infix[i]));
+                }else{
+                    sign.push(std::string(1, infix[i]));
+                }
+            }else if(infix[i] == '+' || infix[i] == '-'){    
+                if(sign.top() == "*" || sign.top() == "/" || sign.top() == "+" || sign.top() == "-"){
+                    postfix = postfix + sign.top() + " ";
+                    sign.pop();
+                    sign.push(std::string(1, infix[i]));
+                }else{
+                    sign.push(std::string(1, infix[i]));
+                }
+            }
+        }
+    }
+    while(!sign.empty()){
+        postfix = postfix + sign.top() + " ";
+        sign.pop();
+    }
+    return postfix;
+}
+
+int Calculator::run_calculate(std::string& infix){
+    std::string input = infix_to_postfix(infix);
+    // std::cout << input << std::endl;
+    if(input == "err"){
+        std::cout << " 계산결과가 0으로 출력됩니다." << std::endl;
+        return 0;   // 에러 발생시 계산결과 0
+    }
+    int result;
+    std::stack<int> numbers;
+
+    for(int i = 0; i < input.size(); i++){
+        if(input[i] == ' '){
+            continue;
+        }
+
+        if(input[i] >= '0' && input[i] <= '9'){
+            int temp = 0;
+            while(input[i] >= '0' && input[i] <= '9'){
+                temp = 10 * temp + static_cast<int>(input[i]) - '0';
+                i++;
+            }
+            numbers.push(temp);
+        }
+        
+        if((input[i] == '+' || input[i] == '-' || input[i] == '*' || input[i] == '/') && numbers.size() < 2){
+            std::cout << "parse error 계산결과가 0으로 출력됩니다." << std::endl;
+            return 0;   // 에러 발생시 계산결과 0
+        }
+        if(input[i] == '+'){
+            int num2 = numbers.top();
+            numbers.pop();
+            int num1 = numbers.top();
+            numbers.pop();
+            numbers.push(num1 + num2);
+        }else if(input[i] == '-'){
+            int num2 = numbers.top();
+            numbers.pop();
+            int num1 = numbers.top();
+            numbers.pop();
+            numbers.push(num1 - num2);
+        }else if(input[i] == '*'){
+            int num2 = numbers.top();
+            numbers.pop();
+            int num1 = numbers.top();
+            numbers.pop();
+            numbers.push(num1 * num2);
+        }else if(input[i] == '/'){
+            int num2 = numbers.top();
+            numbers.pop();
+            int num1 = numbers.top();
+            numbers.pop();
+            numbers.push(num1 / num2);
+        }
+    }
+    result = numbers.top();
+
+    return result;
+}
+
+int main(){
+    Calculator cal;
+    std::string t1[] =
+    {
+        "((2+ 13*5) / 2) * 3",
+        "21 +3",
+        "2 +3 * 5",
+        "2-4*(1+12)",
+        "+3+2",
+        "1 + -3",
+    };
+    int test1[6];
+    for(int i = 0; i < 6; i++){
+        std::cout << t1[i] << std::endl;
+        test1[i] = cal.run_calculate(t1[i]);
+        std::cout << test1[i] << std::endl;
+    }
+
+    return 0;
+}
\ No newline at end of file

doubly_linked_list.cpp

+#ifndef DOUBLY_LINKED_LIST_CPP
+#define DOUBLY_LINKED_LIST_CPP
+
+#include "doubly_linked_list.h"
+
+template <typename T>
+T DoublyLinkedList<T>::front() const{
+    if(!head){  // head 가 NULL 이면 예외처리
+        throw std::__throw_out_of_range("리스트가 비어있습니다.");
+    }
+    return head->data;
+}
+
+template <typename T>
+T DoublyLinkedList<T>::back() const{
+    if(!tail){
+        throw std::__throw_out_of_range("리스트가 비어있습니다.");
+    }
+    return tail->data;
+}
+
+template <typename T>
+size_t DoublyLinkedList<T>::size() const{
+    return node_size;
+}
+
+template <typename T>
+void DoublyLinkedList<T>::push_front(T value){
+    Node<T>* newNode = new Node<T>(value);
+    if(head){
+        newNode->next = head;
+        head->prev = newNode;
+    }else{  // 비어있었다면
+        tail = newNode;
+    }
+    head = newNode;
+    node_size++;
+}
+
+template <typename T>
+void DoublyLinkedList<T>::push_back(T value){
+    Node<T>* newNode = new Node<T>(value);
+    if(tail){
+        newNode->prev = tail;
+        tail->next = newNode;
+    }else{
+        head = newNode;
+    }
+    tail = newNode;
+    node_size++;
+}
+
+template <typename T>
+void DoublyLinkedList<T>::pop_front(){
+    if(!head){
+        throw std::out_of_range("리스트가 비어있습니다.");
+    }
+    Node<T>* temp = head;
+    head = head->next;
+    if(head){
+        head->prev = NULL;
+    }else{
+        tail = NULL;
+    }
+    node_size--;
+    delete temp;
+}
+
+template <typename T>
+void DoublyLinkedList<T>::pop_back(){
+    if(!head){
+        throw std::out_of_range("리스트가 비어있습니다.");
+    }
+    Node<T>* temp = tail;
+    tail = tail->prev;
+    if(tail){
+        tail->next = NULL;
+    }else{
+        tail = NULL;
+    }
+    node_size--;
+    delete temp;
+}
+
+template <typename T>
+void DoublyLinkedList<T>::insert(T value, size_t position){
+    if(position == 0){
+        push_front(value);
+    }else if(position == node_size){
+        push_back(value);
+    }else if(position > 0 && position < node_size){
+        Node<T>* newNode = new Node<T>(value);
+        Node<T>* temp = head;
+        Node<T>* temp_prev = temp;
+        for(int i = 0; i < position; i++){
+            temp_prev = temp;
+            temp = temp->next;
+        }
+        temp_prev->next = newNode;
+        newNode->prev = temp_prev;
+        newNode->next = temp;
+        temp->prev = newNode;
+    }else{
+        throw std::out_of_range("잘못된 위치에 insert하려 합니다.");
+        return;
+    }
+    node_size++;
+}
+
+template <typename T>
+void DoublyLinkedList<T>::remove(T value){
+    if(node_size == 0){
+        std::cout << "리스트가 비어있습니다." << std::endl;
+        return;
+    }
+    // 값이 head에 있을 때
+    if(head->data == value){
+        Node<T>* temp = head;
+        head = head->next;
+        if(head){
+            head->prev = nullptr;
+        }else{
+            tail = nullptr;
+        }
+        delete temp;
+        node_size--;
+        return;
+    }
+    // 값이 head에 없을 때
+    Node<T>* current = head;
+    while(current != NULL){
+        if(current->data == value){
+            Node<T>* prevNode = current->prev;
+            Node<T>* nextNode = current->next;
+
+            if(prevNode){
+                prevNode->next = nextNode;
+            }
+            if(nextNode){
+                nextNode->prev = prevNode;
+            }else{
+                tail = prevNode;
+            }
+            delete current;
+            node_size--;
+            return;
+        }
+        current = current->next;
+    }
+    std::cout << "값 " << value << "을(를) 찾을 수 없습니다.\n";
+}
+
+template <typename T>
+void DoublyLinkedList<T>::clear(){
+    while(head != NULL){
+        pop_front();
+    }
+}
+
+template <typename T>
+bool DoublyLinkedList<T>::empty() const{
+    if(node_size == 0){
+        return true;
+    }else{
+        return false;
+    }
+}
+
+template <typename T>
+void DoublyLinkedList<T>::print() const{
+    Node<T>* temp = head;
+    if(temp != NULL){
+        std::cout << "NULL <-> ";
+    }
+    while(temp != NULL){
+        std::cout << temp->data << " <-> ";
+        temp = temp->next;
+    }
+    std::cout << "NULL" << std::endl;
+}
+
+int main(){
+    DoublyLinkedList<int> dll1;
+    dll1.push_back(3);
+    dll1.push_front(2);
+    dll1.push_back(5);
+    dll1.push_front(1);
+    dll1.print();
+    // 출력결과
+    // NULL <-> 1 <-> 2 <-> 3 <-> 5 <-> NULL
+
+    dll1.insert(4, 3);
+    dll1.print();
+    // 출력결과
+    // NULL <-> 1 <-> 2 <-> 3 <-> 4 <-> 5 <-> NULL
+
+    dll1.remove(4);
+    dll1.print();
+    dll1.remove(4);
+    // 출력결과
+    // NULL <-> 1 <-> 2 <-> 3 <-> 5 <-> NULL
+    // 값 4을(를) 찾을 수 없습니다.
+
+    dll1.clear();
+    dll1.print();
+    // 출력결과
+    // NULL
+
+    return 0;
+}
+
+#endif
\ No newline at end of file

singly_linked_list.c

+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct Node{
+    int data;
+    struct Node* next;
+}Node;
+
+Node* createNode(int data){
+    Node* head = (Node*)malloc(sizeof(Node));
+    if(!head){
+        printf("노드 생성 오류\n");
+        exit(1);
+    }
+    head->data = data;
+    head->next = NULL;
+    return head;
+}
+
+void appendNode(Node** head, int data){
+    Node* newNode = createNode(data);
+    if(*head == NULL){  // 빈 LL 였을 경우
+        *head = newNode;
+        return;
+    }
+    Node* temp = *head;
+    while(temp->next != NULL){  // 마지막 위치 찾기
+        temp = temp->next;
+    }
+    temp->next = newNode;
+}
+
+void insertNode(Node** head, int data, int position){
+    Node* newNode = createNode(data);
+    if(position == 0){
+        newNode->next = *head;
+        *head = newNode;
+        return;
+    }
+    Node* temp = *head;
+    for(int i = 0; i < position - 1 && temp != NULL; i++){
+        temp = temp->next;
+    }
+    if(temp == NULL){
+        printf("insertNode의 위치가 범위를 넘어갑니다.\n");
+        free(newNode);
+        return;
+    }
+    newNode->next = temp->next;
+    temp->next = newNode;
+}
+
+int size(Node* head){
+    int count = 0;
+    if(head == NULL){  // 빈 LL 였을 경우
+        printf("빈 노드입니다.\n");
+        return count;
+    }
+    Node* temp = head;
+    while(temp->next != NULL){  // 마지막 위치 찾기
+        temp = temp->next;
+        count++;
+    }
+    count++;
+    return count;
+}
+
+// data값을 갖는 첫 번째 노드를 제거
+void deleteNode(Node** head, int data){
+    if(*head == NULL){
+        printf("빈 노드입니다.\n");
+        return;
+    }
+    Node* temp = *head;
+    if(temp->data == data){
+        *head = temp->next;
+        free(temp);
+        return;
+    }
+    Node* prev = NULL;
+    while(temp->next != NULL && temp->data != data){
+        prev = temp;
+        temp = temp->next;
+    }
+    if(temp == NULL){
+        printf("삭제할 Data가 없습니다.\n");
+    }
+    prev->next = temp->next;
+    free(temp);
+    return;
+}
+
+void printList(Node* head){
+    Node* temp = head;
+    while(temp != NULL){
+        printf("%d -> ", temp->data);
+        temp = temp->next;
+    }
+    printf("NULL\n");
+}
+
+Node* searchNode(Node* head, int data){
+    if(head == NULL){
+        printf("빈 노드입니다.\n");
+    }
+    Node* temp = head;
+    while(temp != NULL){
+        if(temp->data == data){
+            return temp;
+        }
+        temp = temp->next;
+    }
+    return NULL;
+}
+
+void freeList(Node** head){
+    Node* temp;
+    while(*head != NULL){
+        temp = *head;
+        *head = (*head)->next;
+        free(temp);
+    }
+}
+
+int main(void){
+    Node* node1 = createNode(1);
+
+    appendNode(&node1, 2);
+    appendNode(&node1, 4);
+    appendNode(&node1, 5);
+
+    printf("size : %d\n", size(node1));
+    printList(node1);
+    // 출력결과
+    // size : 4
+    // 1 -> 2 -> 4 -> 5 -> NULL
+
+    insertNode(&node1, 3, 2);
+
+    printf("size : %d\n", size(node1));
+    printList(node1);
+    // 출력결과
+    // size : 5
+    // 1 -> 2 -> 3 -> 4 -> 5 -> NULL
+
+    int searchValue1 = 4;
+    Node* search1 = searchNode(node1, searchValue1);
+    if(search1 != NULL){
+        printf("%d 값이 리스트에 존재합니다.\n", searchValue1);
+    }else{
+        printf("%d 값이 리스트에 존재하지 않습니다.\n", searchValue1);
+    }
+    // 출력결과
+    // 4 값이 리스트에 존재합니다.
+
+    deleteNode(&node1, searchValue1);
+    printf("%d 삭제\n", searchValue1);
+    printList(node1);
+    // 출력결과
+    // 4 삭제
+    // 1 -> 2 -> 3 -> 5 -> NULL
+
+    search1 = searchNode(node1, searchValue1);
+    if(search1 != NULL){
+        printf("%d 값이 리스트에 존재합니다.\n", searchValue1);
+    }else{
+        printf("%d 값이 리스트에 존재하지 않습니다.\n", searchValue1);
+    }
+    // 출력결과
+    // 4 값이 리스트에 존재하지 않습니다.
+
+    freeList(&node1);
+    printf("리스트 제거\n");
+    printList(node1);
+    // 출력결과
+    // 리스트 제거
+    // NULL
+
+    return 0;
+}
\ No newline at end of file