bool QObject::inherits(const char *className) const 简单使用实例

下面是一个简单的使用示例：

#include <QObject>
#include <QDebug>

class MyObject : public QObject
{
    Q_OBJECT
public:
    explicit MyObject(QObject *parent = nullptr) : QObject(parent) {}
};

int main(int argc, char *argv[])
{
    Q_UNUSED(argc)
    Q_UNUSED(argv)

    MyObject obj;
    if (obj.inherits("QObject")) {
        qDebug() << "MyObject inherits QObject";
    }
    if (obj.inherits("QList")) {
        qDebug() << "MyObject inherits QList";
    }

    return 0;
}

在上面的示例中，我们定义了一个名为`MyObject`的类，它继承自`QObject`。在`main`函数中，我们创建了一个`MyObject`类的对象`obj`，并使用`inherits`函数判断它是否是`QObject`和`QList`的子类或实现类。由于`MyObject`直接继承自`QObject`，因此第一个判断返回`true`，而第二个判断返回`false`，因为`MyObject`并没有继承自`QList`。

相关问题

bool ADOConnection::ExecuteSP(const char* spName, const char* params) { try { CString strCmd; strCmd.Format("{ call %s(%s) }", spName, params); 错误

这段代码的错误可能有多种可能性，需要更多的上下文才能确定。根据你提供的代码来看，其中一个可能的错误是 `CString` 类型的 `strCmd` 变量没有被初始化，导致在调用 `Format` 方法时出现错误。你可以尝试在使用 `strCmd.Format` 方法之前对 `strCmd` 进行初始化，例如：

CString strCmd("");
strCmd.Format("{ call %s(%s) }", spName, params);

另外，还需要确保传入的 `spName` 和 `params` 参数值是正确的，并且符合存储过程参数的格式要求。如果问题仍然存在，可以尝试使用调试工具来进一步定位问题。

填充下面这个程序中所有出现// TODO: fill the code这个任务的地方#include <iostream> #include <cstring> #include "ourstring.h" #include "strlib.h" using namespace std; OurString::OurString(){ // TODO: fill the code } OurString::OurString(const char *str){ // TODO: fill the code } OurString::OurString(const OurString &dstr){ // TODO: fill the code } OurString::~OurString(){ // TODO: fill the code } string OurString::toString() const{ // TODO: fill the code } OurString OurString::subStr(unsigned int start, unsigned int n) const{ // TODO: fill the code } bool OurString::operator > (const OurString &dstr) const{ // TODO: fill the code } bool OurString::operator < (const OurString &dstr) const{ // TODO: fill the code } bool OurString::operator == (const OurString &dstr) const{ // TODO: fill the code } unsigned int OurString::length () const{ // TODO: fill the code } const OurString& OurString::operator = (const OurString &dstr){ // TODO: fill the code } const OurString& OurString::operator = (const char *str){ // TODO: fill the code } char& OurString::operator[](int index){ // TODO: fill the code } const OurString OurString::operator + (const OurString &dstr) const{ // TODO: fill the code } const OurString OurString::operator + (const char *str) const{ // TODO: fill the code } const OurString& OurString::operator += (const OurString &dstr){ // TODO: fill the code } const OurString& OurString::operator += (const char *str){ // TODO: fill the code } ostream & operator<<(ostream &os, const OurString &dstr){ // TODO: fill the code } istream & operator>>(istream &is, OurString &dstr){ // TODO: fill the code }

好的，下面是填充后的代码，每个 TODO 已经被替换成相应的实现：

#include <iostream>
#include <cstring>
#include "ourstring.h"
#include "strlib.h"
using namespace std;

OurString::OurString(){
    str = new char[1];
    str[0] = '\0';
}

OurString::OurString(const char *str){
    this->str = new char[strlen(str)+1];
    strcpy(this->str, str);
}

OurString::OurString(const OurString &dstr){
    this->str = new char[dstr.length()+1];
    strcpy(this->str, dstr.str);
}

OurString::~OurString(){
    delete [] str;
}

string OurString::toString() const{
    return string(str);
}

OurString OurString::subStr(unsigned int start, unsigned int n) const{
    if (start >= length()) return OurString();
    n = (n > length() - start) ? length() - start : n;
    return OurString(str + start, str + start + n);
}

bool OurString::operator > (const OurString &dstr) const{
    return strcmp(str, dstr.str) > 0;
}

bool OurString::operator < (const OurString &dstr) const{
    return strcmp(str, dstr.str) < 0;
}

bool OurString::operator == (const OurString &dstr) const{
    return strcmp(str, dstr.str) == 0;
}

unsigned int OurString::length () const{
    return strlen(str);
}

const OurString& OurString::operator = (const OurString &dstr){
    if (this != &dstr) {
        delete [] str;
        str = new char[dstr.length()+1];
        strcpy(str, dstr.str);
    }
    return *this;
}

const OurString& OurString::operator = (const char *str){
    if (this->str != str) {
        delete [] this->str;
        this->str = new char[strlen(str)+1];
        strcpy(this->str, str);
    }
    return *this;
}

char& OurString::operator[](int index){
    return str[index];
}

const OurString OurString::operator + (const OurString &dstr) const{
    OurString s;
    s.str = new char[length() + dstr.length() + 1];
    strcpy(s.str, str);
    strcat(s.str, dstr.str);
    return s;
}

const OurString OurString::operator + (const char *str) const{
    OurString s;
    s.str = new char[length() + strlen(str) + 1];
    strcpy(s.str, this->str);
    strcat(s.str, str);
    return s;
}

const OurString& OurString::operator += (const OurString &dstr){
    *this = *this + dstr;
    return *this;
}

const OurString& OurString::operator += (const char *str){
    *this = *this + str;
    return *this;
}

ostream & operator<<(ostream &os, const OurString &dstr){
    os << dstr.str;
    return os;
}

istream & operator>>(istream &is, OurString &dstr){
    string s;
    is >> s;
    dstr = s.c_str();
    return is;
}