Question

为什么我不能在方法isCaseSensitive中更改对象的assocTab::swap()值？ isCaseSensitive字段在assocTab()构造函数内初始化。 Valgrind输出：

==13666== Conditional jump or move depends on uninitialised value(s)
==13666==    at 0x401341: assocTab::setCaseSensitivity(bool) (assoctable.cpp:117)
==13666==    by 0x401157: assocTab::swap(assocTab&) (assoctable.cpp:68)
==13666==    by 0x4011C3: assocTab::operator=(assocTab const&) (assoctable.cpp:77)
==13666==    by 0x4015FE: main (main.cpp:21)
==13666==

我的方法和isCaseSensitive所属的简化类：

class assocTab{

private:
    struct node{
        node* next;
        char* key;
        int val;

    };
    node* head;
    bool isCaseSensitive;
    void clear();
    void swap(assocTab& l);
public:
    void setCaseSensitivity(bool);
    bool getCaseSensitivity() const;
};

assocTab::assocTab(){
    head = NULL;
    setCaseSensitivity(true);
}
assocTab::assocTab(const assocTab& l){
    node *src, **dst;
    head = NULL;
    src = l.head;
    dst = &head;
    try{
        while(src){
            *dst = new node (*src);
            src = src->next;
            dst = &((*dst)->next);
        }
    }catch(...){
        clear();
        throw;
    };
}
void assocTab::swap(assocTab& l){

    bool swpCS = getCaseSensitivity();
    bool swpCS2 = l.getCaseSensitivity();
    l.setCaseSensitivity(swpCS);
    setCaseSensitivity(swpCS2);  //line 68

    std::swap(l.head, head);
}
void assocTab::setCaseSensitivity(bool isCS){
    if(isCS)    //line 117
        isCaseSensitive = true;
    else
        isCaseSensitive = false;
}
bool assocTab::getCaseSensitivity() const{
    return isCaseSensitive;
}
assocTab& assocTab::operator= (const assocTab& l){
    if (&l == this)
    return *this;
    assocTab t(l);
    swap(t);

    return *this;
}

Answer 1

您的复制构造函数似乎没有复制isCaseSensitive的值。因此，当调用operator+()方法并使用复制构造函数创建本地副本时，当您使用本地副本调用swap时，该值仍未初始化。

改变类字段C ++的值 - '条件跳转或移动取决于酉值'

1 个答案: