static_cast關鍵字（編譯時類型檢查）

代碼如下：

#include <iostream> using namespace std; class Base{ public :Base(const int baseData){m_baseData = baseData;}void print()const{cout << "m_baseData is " << m_baseData << endl;} private:int m_baseData; };class Upgrade :public Base{ public:Upgrade(const int upgradeData) :Base(upgradeData){m_upgradeData = upgradeData;}void setGradeData(const int &data){m_upgradeData = data;}void print()const{cout << "m_upgradeData is " << m_upgradeData << endl;} private:int m_upgradeData; };int main(){double double_1 = 100.0001;int a = static_cast<int>(double_1);cout << "double_1 is " << double_1 << endl;cout << "a is " << a << endl;Base *base = new Base(100);cout << "base print:";base->print();Upgrade *upgrade = new Upgrade(101);cout << "upgrade print:";upgrade->print();Base *castBase1 = static_cast<Base*>(upgrade);cout << "castBase1 print:";castBase1->print();Upgrade *caseUpgrade1 = static_cast<Upgrade*>(upgrade);cout << "caseUpgrade1 print:";caseUpgrade1->print();Upgrade *caseUpgrade2 = static_cast<Upgrade*>(base);cout << "caseUpgrade2 print:";caseUpgrade2->print();Upgrade *caseUpgrade3 = (Upgrade*)base;cout << "caseUpgrade3 print:";caseUpgrade3->print();cout << "sizeof(*caseUpgrade3):" << sizeof(*caseUpgrade3) << endl;caseUpgrade3->setGradeData(1);cout << "sizeof(*caseUpgrade3):" << sizeof(*caseUpgrade3) << endl;Base *base_base = upgrade;cout << "base_base print:";base_base->print();delete upgrade;//delete base;getchar();return 0; }

運行截圖如下：

這里就提一點：

Upgrade *caseUpgrade3 = (Upgrade*)base;cout << "caseUpgrade3 print:";caseUpgrade3->print();cout << "sizeof(*caseUpgrade3):" << sizeof(*caseUpgrade3) << endl;caseUpgrade3->setGradeData(1);cout << "sizeof(*caseUpgrade3):" << sizeof(*caseUpgrade3) << endl;Base *base_base = upgrade;cout << "base_base print:";base_base->print();delete upgrade;//delete base;

這里把子類指針強指到了父類，并且還修改了子類的值，這真是個騷包的操作！！！

我的電腦是小端系統。

但是不能對base進行析構，會報如下的錯誤。

delete base;

原因是：分配了len長度的空間，卻用到了len + 1的長度，釋放的時候就報錯了

總結

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