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数据文件只是一个整数，一个字符串，另一个整数。例如：

20 Bob 550

这是代码：

#include <iostream>
#include <iomanip>
#include <fstream>
#include <string>
using namespace std;

struct RECORD
{
    int ID;
    string name;
    float balance;
};

void Display(char fname[])
{
    RECORD st;
    fstream f;
    f.open(fname, ios::in|ios::binary);
    cout<<fixed<<showpoint<<setprecision(2);
    for(int i=1; i<=5; ++i)
    {
        //read a record file from the RAF
        f.read((char*)&st, sizeof(st));
        cout<<st.ID<<'\t'<<st.name<<'\t'<<st.balance<<endl;
    }
    f.close();
}

int main()
{
    //initalize the RAF with dummy record 0, "nnn", 0.0
    fstream g;
    g.open("data.raf", ios::out|ios::binary);
    RECORD dummy={0, "nnn", 0.0};
    for(int i=1; i<=5; ++i)
    {
        g.write((char*)&dummy, sizeof(RECORD));
    }
    g.close();

    Display("data.raf");

    //copy text file into RAF
    fstream ftxt;
    fstream fraf;

    //open text file to read from
    ftxt.open("data.txt", ios::in);

    //open RAF to write
    fraf.open("data.raf", ios::out|ios::binary);

    for(int i=1; i<=5; ++i)
    {
        ftxt>>dummy.ID>>dummy.name>>dummy.balance;
        int byteOfSet = (dummy.ID/10-1)*sizeof(RECORD);

        //seekp to put (write)
        //seekg to get (read)
        fraf.seekp(byteOfSet, ios::beg);

        //beg   from beginning of file
        fraf.write((char*)&dummy, sizeof(RECORD));
    }

    //deposit 100 in ID #40
    int id;
    cout<<"Enter an ID number: ";
    cin>>id;
    fraf.open("data.raf", ios::in|ios::out|ios::binary);
    int byteOfSet = (id/10-1)*sizeof(RECORD);
    fraf.seekg(byteOfSet, ios::beg);
    fraf.read((char*)&dummy, sizeof(RECORD));
    dummy.balance += 100;

    //put the updated record back into the same place
    fraf.seekp(byteOfSet, ios::beg);
    fraf.write((char*)&dummy, sizeof(RECORD));
    //fraf.close();

    ftxt.close();
    fraf.close();
    Display("data.raf");

    system("pause");
    return 0;
}

代码运行然后就死在控制台中......我不知道出了什么问题。我认为这可能与重新进入英国皇家空军有关，但这只是我的猜测。

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