C++ 如何重复利用一个内存地址块

时间：2021-11-01 18:54:56
 #include<iostream>

 using namespace std;

 const int size = ;

 double buf[size] = {};

 int main(int argv ,char * args[]) {

     double *p1,*p2;

      p1 = new double[size];

      p2 = new (buf)double[size];

      for (int i = ; i < size; i++) {

          p1[i]=p2[(i+)%size]=i+;

          cout << "p1== " << &p1[i] << "    p1[i]=="<<p1[i]<<"   "<< endl;

      }

      cout << "---------------华丽丽的分割线-----------------------" << endl;

      for (int i = ; i < size; i++) {

          cout << "p2== " << &p2[i] << "    p2[i]==" << p2[i] << "   " << endl;

      }

      cout << "---------------一大波内存袭来！-----------------------" << endl;

      double *p3, *p4;

      p3 = new double[size];

      p4 = new (buf)double[size];

      for (int i = ; i < size; i++) {

          p3[i] = p4[(i + ) % size] = i + ;

          cout << "p3== " << &p3[i] << "    p3[i]==" << p3[i] << "   " << endl;

      }

      cout << "---------------华丽丽的分割线-----------------------" << endl;

      for (int i = ; i < size; i++) {

          cout << "p4== " << &p4[i] << "    p4[i]==" << p4[i] << "   " << endl;

      }

      cout << "###################华丽丽的分割线########################" << endl;

      //数组指针

      double *p[] = {p1,p2,p3,p4};

      for (int i = ; i < ; i++)

          for (int j = ; j < size; j++) {

              cout << "p["<<i<<"]== " << &p[i][j] << "    p["<<i<<"]"<<"["<<j<<"]==" << p[i][j] << "   " << endl;

          }

      for (int i = ; i < ; i++) {

           //释放new创建的内存

          if (p[i]!=buf)  delete [] p[i] ;

      }

      cout << "内存释放之后" << endl;

      for (int i = ; i < size; i++) {

          cout << "p1== " << &p1[i] << "    p1[i]==" << p1[i] << "   " << endl;

      }

      cin.get();

     return ;

 }
 p1== 0038DC28    p1[i]==

 p1== 0038DC30    p1[i]==

 p1== 0038DC38    p1[i]==

 p1== 0038DC40    p1[i]==

 p1== 0038DC48    p1[i]==

 p1== 0038DC50    p1[i]==

 p1== 0038DC58    p1[i]==

 p1== 0038DC60    p1[i]==

 p1== 0038DC68    p1[i]==

 p1== 0038DC70    p1[i]==

 ---------------华丽丽的分割线-----------------------

 p2== 0125C2D0    p2[i]==

 p2== 0125C2D8    p2[i]==

 p2== 0125C2E0    p2[i]==

 p2== 0125C2E8    p2[i]==

 p2== 0125C2F0    p2[i]==

 p2== 0125C2F8    p2[i]==

 p2== 0125C300    p2[i]==

 p2== 0125C308    p2[i]==

 p2== 0125C310    p2[i]==

 p2== 0125C318    p2[i]==

 ---------------一大波内存袭来！-----------------------

 p3== 0038B1F8    p3[i]==

 p3== 0038B200    p3[i]==

 p3== 0038B208    p3[i]==

 p3== 0038B210    p3[i]==

 p3== 0038B218    p3[i]==

 p3== 0038B220    p3[i]==

 p3== 0038B228    p3[i]==

 p3== 0038B230    p3[i]==

 p3== 0038B238    p3[i]==

 p3== 0038B240    p3[i]==

 ---------------华丽丽的分割线-----------------------

 p4== 0125C2D0    p4[i]==

 p4== 0125C2D8    p4[i]==

 p4== 0125C2E0    p4[i]==

 p4== 0125C2E8    p4[i]==

 p4== 0125C2F0    p4[i]==

 p4== 0125C2F8    p4[i]==

 p4== 0125C300    p4[i]==

 p4== 0125C308    p4[i]==

 p4== 0125C310    p4[i]==

 p4== 0125C318    p4[i]==

 ###################华丽丽的分割线########################

 p[]== 0038DC28    p[][]==

 p[]== 0038DC30    p[][]==

 p[]== 0038DC38    p[][]==

 p[]== 0038DC40    p[][]==

 p[]== 0038DC48    p[][]==

 p[]== 0038DC50    p[][]==

 p[]== 0038DC58    p[][]==

 p[]== 0038DC60    p[][]==

 p[]== 0038DC68    p[][]==

 p[]== 0038DC70    p[][]==

 p[]== 0125C2D0    p[][]==

 p[]== 0125C2D8    p[][]==

 p[]== 0125C2E0    p[][]==

 p[]== 0125C2E8    p[][]==

 p[]== 0125C2F0    p[][]==

 p[]== 0125C2F8    p[][]==

 p[]== 0125C300    p[][]==

 p[]== 0125C308    p[][]==

 p[]== 0125C310    p[][]==

 p[]== 0125C318    p[][]==

 p[]== 0038B1F8    p[][]==

 p[]== 0038B200    p[][]==

 p[]== 0038B208    p[][]==

 p[]== 0038B210    p[][]==

 p[]== 0038B218    p[][]==

 p[]== 0038B220    p[][]==

 p[]== 0038B228    p[][]==

 p[]== 0038B230    p[][]==

 p[]== 0038B238    p[][]==

 p[]== 0038B240    p[][]==

 p[]== 0125C2D0    p[][]==

 p[]== 0125C2D8    p[][]==

 p[]== 0125C2E0    p[][]==

 p[]== 0125C2E8    p[][]==

 p[]== 0125C2F0    p[][]==

 p[]== 0125C2F8    p[][]==

 p[]== 0125C300    p[][]==

 p[]== 0125C308    p[][]==

 p[]== 0125C310    p[][]==

 p[]== 0125C318    p[][]==

 内存释放之后

 p1== 0038DC28    p1[i]==-1.45682e+144

 p1== 0038DC30    p1[i]==-1.45682e+144

 p1== 0038DC38    p1[i]==-1.45682e+144

 p1== 0038DC40    p1[i]==-1.45682e+144

 p1== 0038DC48    p1[i]==-1.45682e+144

 p1== 0038DC50    p1[i]==-1.45682e+144

 p1== 0038DC58    p1[i]==-1.45682e+144

 p1== 0038DC60    p1[i]==-1.45682e+144

 p1== 0038DC68    p1[i]==-1.45682e+144

 p1== 0038DC70    p1[i]==-1.45682e+144

这样，可以对内存进行很好的利用，避免内存泄露。而导致系统运行越来越慢！

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