-2 
void updatebfile(char filename[MAX])
{

fstream writereadb;

char cont='y';
char filenameb [MAX];
int i=1;
int record;

student s;

strcpy(filenameb,filename);
strcat(filenameb,".dat");

writereadb.open(filenameb,ios::in | ios::out | ios::binary  );


cout<<"------------------------------"
    <<endl;

cout<<"Begin updating of binary file "
    <<filenameb
    <<endl
    <<endl;

cout<<"Information for student file"
    <<endl
    <<endl;


while ( writereadb.read (reinterpret_cast <char *>(&s), sizeof (s) ) )
{

    cout<<i
        <<'\t'
        <<s.identity
        <<" "
        <<s.name
        <<endl;

    i++;


}
writereadb.clear();

do
{   
cout<<endl
    <<"Update record: ";
cin>>record;

cout<<endl
    <<"Student id: ";   

writereadb.seekg ( (record - 1) * sizeof(s), ios::beg);
writereadb.read (reinterpret_cast <char *>(&s), sizeof (s));    

cout<<s.identity
    <<endl; 

cout<<"Update the name: "; 
cin.getline(s.name,50); //My programme does not stop at this line to read in an input for some reason
//cin.clear();
    //cin.ignore(200,'\n'); 

writereadb.seekp((record-1)*sizeof(student),ios::beg);  
writereadb.write (reinterpret_cast <const char *>(&s), sizeof (s));

cout<<"Any more update (y/n) :";
cin>>cont;//

}while (cont=='y');

writereadb.close();
 }

我的程序运行良好，除了在程序快结束时遇到cin.getline(s.name,50). 程序不会停止读取输入并继续运行。

我试过把它放在cin.clear(); cin.ignore;后面cin.getline(s.name,50)，它可以工作，但它不会将它存储s.name到二进制文件中。

4

2 回答 2

1

cin.ignore(); 在之前添加cin.getline(s.name,50);

于 2013-01-13T16:11:51.803 回答
0

我必须添加

cin.clear();

cin.ignore(200,'\n');

在 cin>> 期间使用 >> 运算符清除 '\n'

于 2013-01-13T17:01:16.743 回答