listC++

#include <iostream>
using namespace std;
typedef struct _node{
    int data;
    struct _node* next;
    _node(int e,_node* p=nullptr):data(e),next(p){}
}node;

class list{
public:
    list():m_start(new node(-1,nullptr)),m_tail(m_start),m_length(0){}
    ~list(){
        while(m_start != nullptr){
            node* pdel = m_start;
            m_start = m_start->next;
            delete pdel;
        }
        m_start = m_tail = nullptr;
    }

    void append(int e);
    bool insert(int index,int e);
    void remove(int e);
    int find(int e);
    void replace(int olddata,int newdata);
    int length();
    int getdata(int index);
private:
            node* m_start;
            node* m_tail;
            int   m_length;
};

void list::append(int e){
    node* pnew = new node(e,nullptr);
    m_tail->next = pnew;
    m_tail = pnew;
    ++m_length;
}

bool list::insert(int index,int e){
    if(index < 0 || index > m_length){
        cout << "index not in the range\n";
        return false;
    }else{
        int i = 0;
        node* prevence = m_start;
        for(; i < index ; ++i){
            prevence = prevence->next;
        }
        node* pnew = new node(e,nullptr);
        pnew->next = prevence->next;
        prevence->next = pnew;
        ++m_length;
        return true;
    }
}
int list::find(int e){
    int i = 0;
    node* prevence = m_start;
    for(; i < m_length; ++i){
        if(prevence->next->data == e){
            return i;
        }
        prevence = prevence->next;
    }
    return -1;
}

void list::remove(int e){
    int i = 0;
    node* prevence = m_start;
    for (; i < m_length ; ++i){
        if(prevence->next->data == e){
            node* pdel = prevence->next;
            prevence->next = pdel->next;
            delete pdel;
            --m_length;
        }
        prevence = prevence->next;
    }
}
void list::replace(int olddata,int newdata){
    int i = 0;
    node* prevence = m_start;
    for(; i < m_length; ++i){
        if(prevence->next->data == olddata){
            prevence->next->data = newdata;
        }
        prevence = prevence->next;
    }
}
int list::length(){
    return m_length;
}
int list::getdata(int index){
    if(index < 0 || index > m_length-1){
        cout << "index not in the range\n";
        return 0;
    }else{
        int i = 0;
        node* prevence = m_start;
        for(; i < index ; ++i){
            prevence = prevence->next;
        }
        return prevence->next->data;
    }
}

int main(){
    list li;
    for(int i = 0 ; i < 10 ; ++i){
        li.append(i);
    }
    li.insert(0,-1);
    for(int i = 0 ; i < li.length(); ++i){
        cout << li.getdata(i) << ends; 
    }
    cout << endl;

    li.remove(5);
    for (int i = 0; i < li.length(); ++i){
        cout << li.getdata(i) << ends;
    }
    cout << endl;

    li.append(-1);
    li.replace(-1,0);
    for (int i = 0; i < li.length(); ++i){
        cout << li.getdata(i) << ends;
    }
    cout << endl;
    cout << "8 index is :" << li.find(8) << endl;
    return 0;
}