C++各种类型变量所占大小

#include <iostream>#include <string>using namespace std;class A{};class A2{};class B : public A{};class C : public virtual A {};class D : public A, public A2 {};class Base {public:int a;char b;  //字节对齐，占用4个字节static c; //存放在静态存储区，sizeof只能计算所占栈区的大小virtual f(){ cout<<"virtual fun"<<endl; } //虚指针};class Derive : public Base {public:int d;}; //要包括子类大小class Derive1 : public virtual Base {public:int d;}; //要包括子类大小和指向基类指针int main(){printf("32位主机各个类型占用大小\n");printf("sizeof bool is %d,\nsize of char is %d,\nsize of short is %d,\nsize of short int is %d,\n\size of int is %d,\nsize of long int is %d,\nsize of float is %d,\nsize of long is %d,\nsize of double is %d,\n\size of long double is %d,\nsize of pointer is %d\n,size of string is %d\n,size of string point is %d\n",sizeof(bool),sizeof(char),sizeof(short),sizeof(short int), sizeof(int),\sizeof(long int),sizeof(float),sizeof(long),sizeof(double),sizeof(long double),sizeof(int *),sizeof(string),sizeof(string *));printf("size of empty class A is %d,\nsize of empty class B is %d,\nsize of empty class C is %d,\nsize of empty class D is %d\n",sizeof(A), sizeof(B), sizeof(C), sizeof(D)); Base *base=new Derive; printf("size of Base class is %d,\nsize of Derive class is %d,\nsize of Base pointer is %d,\nsize of Derive1 is %d\n",sizeof(Base),sizeof(Derive),sizeof(base),sizeof(Derive1));return 1;}

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