文件操作

Posted 2021-06-11 satellite&

  1 #include <iostream>
  2 #include <cstdlib>
  3 #include <fstream>
  4 using namespace std;
  5 
  6 void bubblesort(int arr[],int n);
  7 int main()
  8 {
  9     fstream f("first.dat",ios::in|ios::out|ios::binary);
 10     if(!f)
 11     {
 12         cerr<<"first open error!"<<endl;
 13         exit(1);
 14     }
 15     fstream s("second.dat",ios::in|ios::out|ios::binary);
 16     if(!f)
 17     {
 18         cerr<<"second open error!"<<endl;
 19         exit(1);
 20     }
 21     int i;
 22     int z[10];
 23     cout<<"please enter 10 integers:";
 24     for(i=0;i<10;i++)
 25     {
 26         cin>>z[i];
 27     }
 28     cout<<"integers:";
 29     for(i=0;i<10;i++)
 30     {
 31         cout<<"z"<<i<<": "<<z[i]<<"  ";
 32     }
 33     cout<<endl;
 34 
 35     for(i=0;i<5;i++)
 36     {
 37         f.write((char*)&z[i],sizeof(z[i]));
 38     }
 39     for(i=5;i<10;i++)
 40     {
 41         s.write((char*)&z[i],sizeof(z[i]));
 42     }
 43 
 44     int z1[5]={0};
 45     s.seekg(0,ios::beg);
 46     cout<<"second:";
 47     for(i=0;i<5;i++)
 48     {
 49         s.read((char *)&z1[i],sizeof(z1[i])); //
 50         cout<<z1[i]<<"  ";
 51     }
 52     cout<<endl;
 53 
 54     for(i=0;i<5;i++)
 55     {
 56         f.write((char *)&z1[i],sizeof(z1[0]));
 57     }
 58     f.seekg(0,ios::beg);
 59     int z2[10]={0};
 60     cout<<"first:";
 61     for(i=0;i<10;i++)
 62     {
 63         f.read((char *)&z2[i],sizeof(z2[0]));
 64         cout<<z2[i]<<"  ";
 65     }
 66     cout<<endl;
 67 
 68     bubblesort(z2,10);
 69     cout<<"after sort:";
 70     for(i=0;i<10;i++)
 71         cout<<z2[i]<<"  ";
 72     cout<<endl;
 73     s.seekp(0,ios::beg);
 74     for(i=0;i<10;i++)
 75     {
 76         s.write((char *)&z2[i],sizeof(z2[i]));
 77     }
 78     s.seekg(0,ios::beg);
 79     int z3[10]={0};
 80     cout<<"second:";
 81     for(i=0;i<10;i++)
 82     {
 83         s.read((char *)&z3[i],sizeof(z3[0])); //
 84         cout<<z3[i]<<"  ";
 85     }
 86     cout<<endl;
 87     f.close();
 88     s.close();
 89     return 0;
 90 }
 91 void bubblesort(int arr[],int n)
 92 {
 93     int temp;
 94     for(int i=1;i<n;i++)
 95         for(int j=0;j<n-i;j++)
 96         {
 97             if(arr[j]>arr[j+1])
 98             {
 99                 temp=arr[j];
100                 arr[j]=arr[j+1];
101                 arr[j+1]=temp;
102             }
103         }
104 }