[C++] Exception / Error Handling 연습하기

C++에서 Error Handling은 에러가 날 부분에서 throw, throw 코드를 동작시키는 부분에서 try/catch를 통해 이루어진다.

Java와 똑같다. 그리고 당연하게도 Exception 클래스를 직접 만들 수도 있다.

아래는 학교 PPT에 나온 예제를 바탕으로 코드를 완성시켜 본 것이다.

내 git hub 에서도 찾아볼 수 있다.

https://github.com/lx5475/cpp_practice/blob/master/error_handling.cpp

/* Error Handling */
#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <string>
 
using namespace std;
 
class StackException {
protected:
    const string msg;
public:
    StackException(const string& msg) : msg(msg) {};
    void print() const { cout << msg << endl; }
};
 
template <class T>
class StackSizeException : public StackException {
    T value;
public:
    StackSizeException(const string& msg, const T& value) : StackException(msg), value(value) {};
    void print() const { cout << msg << " " << value << endl; }
};
 
class CharStack {
    int size;
    int top;
    char* s;
public:
    CharStack(int sz) {
        if (sz <= 0) throw StackSizeException<int>("Invalid stack size.", sz);
        top = 0;
        size = sz;
        s = new char[size];
    }
    CharStack(const CharStack& charStack) {
        delete[] s;
        top = charStack.top;
        size = charStack.size;
        s = new char[size];
        for (int i = 0; i < top; i++) {
            s[i] = charStack.s[i];
        }
    }
    ~CharStack() {
        delete[] s;
    }
    CharStack& operator= (const CharStack& charStack) {
        delete[] s;
        top = charStack.top;
        size = charStack.size;
        s = new char[size];
        for (int i = 0; i < top; i++) {
            s[i] = charStack.s[i];
        }
        return *this;
    }
    void push(char c) { 
        if (top == size) throw StackException("Stack is full.");
        s[top++] = c; 
    }
    char pop() {
        if (top == 0) throw StackException("Stack is empty.");
        char r = s[--top];
        s[top] = '\0';
        return r;
    }
    void print() const {
        for (int i = 0; i < top; i++) {
            cout << s[i];
        }
        cout << endl;
    }
};
 
int main() {
    int SIZE = 20;
    CharStack cs(SIZE);
 
    // push error test
    cout << "<push error test>" << endl;
    string testChar = "Hello world, I'm Jieun.";
    try {
        for (int i = 0; i < testChar.size(); i++) {
            cs.push(testChar.at(i));
        }
    }
    catch (const StackException& e) {
        e.print();
    }
    cs.print();
 
    // copy constructor test
    cout << "<copy constructor test>" << endl;
    CharStack cs2(cs);
    cs2.print();
 
    // assignment operator test
    cout << "<assignment operator test>" << endl;
    CharStack cs3 = cs;
    cs3.print();
 
    // pop error test
    cout << "<pop error test>" << endl;
    try {
        for (int i = 0; i < SIZE + 1; i++) {
            cs.pop();
        }
    }
    catch (const StackException& e) {
        e.print();
    }
    cs.print();
 
    // constructor error test
    cout << "<constructor error test>" << endl;
    try {
        CharStack cs2(-3);
    }
    catch (const StackSizeException<int>& e) {
        e.print();
    }
    
}