#include <iostream>
#include <stdlib.h>
using namespace std;//如果数组变量被传入函数中做sizeof()运算，则和指针的运算没有区别。
void Func( char str[100] )
{cout<<"Fun: == "<<sizeof(str)<<endl;//4字节的指针
}int main()
{char str[] = "Hello";char *p = str;int n = 10;cout<<"str == "<<sizeof(str)<<endl;//结果=6=strlen("Hello")+1;数值中要留一个元素保存字符串结束符
    Func(str);//2个结果都是4，win32下，指针和int都是4字节cout << "p ==" << sizeof(p) << endl;cout << "n ==" << sizeof(n) << endl;//结果4void *q = malloc(100);//100字节的堆内存cout << "void * == " << sizeof(q) << endl;//还是4(指针类型的大小)char *ch = (char *)malloc(sizeof(char)*10);cout << "char * == " <<sizeof(ch) << endl;//还是4(指针类型的大小)return 0;
}
//数组和指针的sizeof()是有区别的。
//对于指针，不论何种类型，其大小都是4字节的。

#include <iostream>
using namespace std;class A
{
public:int i;//4
};
class AA
{
public:double d;int i;//8+4+4（补全）
};
class B
{
public:char ch;//1
};
class C
{
public:int i;short j;//4+2+2(补全)
};
class D
{
public:int i;short j;char ch;//4+2+1+1(补全)
};
class E
{
public:int i;int ii;short l;char ch;char chr;//4+4+2+1+1
};
class F
{
public:int i;int ii;int iii;short j;char ch;char chr;//4+4+4+2+1+1
};
class FF
{
public:short j;int i;char ch;int ii;char chr;int iii;//2+2（补全）+4+1+3（补全）+4+1+3（补全）+4=24
};
int main()
{cout<<"sizeof(double) == "<<sizeof(double)<<endl;//4字节cout<<"sizeof(float) == "<<sizeof(float)<<endl;//4字节cout<<"sizeof(int) == "<<sizeof(int)<<endl;//4字节cout<<"sizeof(short) == "<<sizeof(short)<<endl;//2cout<<"sizeof(char) == "<<sizeof(char)<<endl<<endl;//1
cout<<"sizeof(A) == "<<sizeof(A)<<endl;cout<<"sizeof(AA) == "<<sizeof(AA)<<endl;//最宽的类型是8字节的。cout<<"sizeof(B) == "<<sizeof(B)<<endl;cout<<"sizeof(C) == "<<sizeof(C)<<endl;cout<<"sizeof(D) == "<<sizeof(D)<<endl;cout<<"sizeof(E) == "<<sizeof(E)<<endl;cout<<"sizeof(F) == "<<sizeof(F)<<endl;cout<<"sizeof(FF) == "<<sizeof(FF)<<endl;//同样的类型个数，只是顺序变了，就不一样了。return 0;
}

#include <iostream>
using namespace std;
class Base
{
public:Base(int x):a(x){}void print(){cout<<"base"<<endl;}
private:int a;
};
class Dervied:public Base
{
public:Dervied(int x):Base(x-1),b(x){}void print(){cout<<"Dervied"<<endl;}
private:int b;
};
class A
{
public:A(int x):a(x){}virtual void print(){cout<<"A"<<endl;}
private:int a;
};
class B:public A
{
public:B(int x):A(x-1),b(x){}virtual void print(){cout<<"B"<<endl;}
private:int b;
};int main()
{Base obj1(1);cout<<"size of base obj1 is "<<sizeof(obj1)<<endl;Dervied obj2(2);cout<<"size of Dervied obj2 is "<<sizeof(obj2)<<endl;A a(1);cout<<"size of A obj is "<<sizeof(a)<<endl;B b(2);cout<<"size of B obj is "<<sizeof(b)<<endl;return 0;
}

#include <iostream>
using namespace std;
class A{};
class B{};
class C:public A,public B{};
class D:virtual public A{};
class E:virtual public A,virtual public B{};
class F
{
public:int a;static int b;
};
int F::b = 10;
int main()
{cout<<"sizeof(A) =="<<sizeof(A)<<endl;cout<<"sizeof(B) =="<<sizeof(B)<<endl;cout<<"sizeof(C) =="<<sizeof(C)<<endl;cout<<"sizeof(D) =="<<sizeof(D)<<endl;cout<<"sizeof(E) =="<<sizeof(E)<<endl;cout<<"sizeof(F) =="<<sizeof(F)<<endl;return 0;
}