C++程序代码的内存结构分析

C++程序内部的结构，同C程序的内部结构，也是分段的，一般分为代码段、堆、栈、数据段等。可以通过下面的代码来证明：

cclassAddress.hpp 文件：

#ifndef cclassAddress_hpp
#define cclassAddress_hpp

class cclassAddress
{
public:
    cclassAddress();
    int getNum1();
    void setNum1(int a);

private:
    int mPrvNum1;
public:
    char mpubChar1;
};

#endif /* cclassAddress_hpp */

cclassAddress.cpp文件：

#include "cclassAddress.hpp"
#include <iostream>

using namespace std;

cclassAddress::cclassAddress()
{
    cout << __FILE__ << ":" << __LINE__ <<":"<<__FUNCTION__<<"\tlocation is\t"<<(void*)&(__FUNCTION__)<<endl;
    mPrvNum1=0;
    mpubChar1=0;
}

int cclassAddress::getNum1()
{
    cout << __FILE__ << ":" << __LINE__ <<":"<<__FUNCTION__<<"\tlocation is\t"<<(void*)&(__FUNCTION__)<<endl;
    cout<<"mPrvNum1 location is\t"<<(void*)&(mPrvNum1)<<endl;
    return mPrvNum1;
}

void cclassAddress::setNum1(int a)
{
    cout << __FILE__ << ":" << __LINE__ <<":"<<__FUNCTION__<<"\tlocation is "<<(void*)&(__FUNCTION__)<<endl;
    this->mPrvNum1 = a;
}

main文件：

#include "cclassAddress.hpp"
#include <iostream>

int main(int argc, const char * argv[]) {
    std::cout<<__FILE__ << ":" << __LINE__<<":"<<__FUNCTION__ << "\t"<<(void*)&__FUNCTION__<<endl;

    cclassAddress classAdd;
    cout << __FILE__ << ":" << __LINE__ << ":" <<"local classAdd: location is\t"<< (void*)&classAdd << endl;
    classAdd.setNum1(10);
    int a = classAdd.getNum1();
    cout << __FILE__ << ":" << __LINE__ << ":" <<"local a: location is\t"<< (void*)&a << endl;
    cout << __FILE__ << ":" << __LINE__ << ":" <<"public classAdd.mpubChar1: location is\t"<< (void*)&classAdd.mpubChar1 << endl;

    static int sIntA=10;
    cout << __FILE__ << ":" << __LINE__ << ":" <<"static int sIntA: location is\t"<< (void*)&sIntA << endl;

    cout<<"================="<<endl;
    cclassAddress *p_classAdd = new cclassAddress();
    cout << __FILE__ << ":" << __LINE__ << ":" <<"local *p_classAdd: location is\t"<< (void*)&p_classAdd << endl;
    cout << __FILE__ << ":" << __LINE__ << ":" <<"local &(*p_classAdd): location is\t"<< &(*p_classAdd) << endl;
    p_classAdd->setNum1(11);
    p_classAdd->getNum1();
    cout << __FILE__ << ":" << __LINE__ << ":" <<"public p_classAdd->mpubChar1: location is\t"<< (void*)&(p_classAdd->mpubChar1) << endl;
    delete p_classAdd;
    return 0;
}

程序的执行结果：
/Users/huGuohua/xcode/cpp_study/cpp_study/main.cpp:167:main   0x1000235a2
/Users/huGuohua/xcode/cpp_study/cpp_study/cclassAddress.cpp:16:cclassAddress   location is   0x1000236dd
/Users/huGuohua/xcode/cpp_study/cpp_study/main.cpp:170:local classAdd: location is   0x7ffeefbff438
/Users/huGuohua/xcode/cpp_study/cpp_study/cclassAddress.cpp:30:setNum1   location is 0x100023717
/Users/huGuohua/xcode/cpp_study/cpp_study/cclassAddress.cpp:23:getNum1   location is   0x1000236f9
mPrvNum1 location is   0x7ffeefbff438
/Users/huGuohua/xcode/cpp_study/cpp_study/main.cpp:173:local a: location is   0x7ffeefbff434
/Users/huGuohua/xcode/cpp_study/cpp_study/main.cpp:174:public classAdd.mpubChar1: location is   0x7ffeefbff43c
/Users/huGuohua/xcode/cpp_study/cpp_study/main.cpp:177:static int sIntA: location is   0x100024350
=================
/Users/huGuohua/xcode/cpp_study/cpp_study/cclassAddress.cpp:16:cclassAddress   location is   0x1000236dd
/Users/huGuohua/xcode/cpp_study/cpp_study/main.cpp:181:local *p_classAdd: location is   0x7ffeefbff428
/Users/huGuohua/xcode/cpp_study/cpp_study/main.cpp:182:local &(*p_classAdd): location is   0x1039110a0
/Users/huGuohua/xcode/cpp_study/cpp_study/cclassAddress.cpp:30:setNum1   location is 0x100023717
/Users/huGuohua/xcode/cpp_study/cpp_study/cclassAddress.cpp:23:getNum1   location is   0x1000236f9
mPrvNum1 location is   0x1039110a0
/Users/huGuohua/xcode/cpp_study/cpp_study/main.cpp:185:public p_classAdd->mpubChar1: location is   0x1039110a4
Program ended with exit code: 0

根据以上的结果，可以发现如下规律：
不管是main函数还是类内部的函数，地址在一起，放在代码段的；
不管是普通函数中的变量还是类中的变量，地址在一起，放在栈段的；
static的的变量，地址放在全局变量的数据段；
如果一个对象是用new创建的，他的数据放在堆中；

这就是内存中的进程的几个段：
代码段存放可执行代码、字符串常量、常量数据；
数据段存放已初始化全局变量、静态变量；
栈存放局部变量、函数参数；
堆是用来动态内存分配的；

由此可见：
C和C++的区别，只是从开发人员的角度来看，他的代码是不同，在内存中的结构是完全一样的。如果把类名和域运算符和成员函数看成一个整体，那么C++的代码，就是C结构的面向过程的了。

C++程序代码的内存结构分析

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