在c ++中搜索.txt文件只得到第一行

Question

I got some sort of room reservation program so i wanna search in .txt file so i can find the pre reserved rooms .

the Problem is:

The search function only reads the first line in the .txt file so when i enter a duplicated information it checks only the first line
can u help me out with it Thanks

int search(int search_num){    
string search= to_string(search_num);
int offset;
string line ;
ifstream myfile;
myfile.open("booked.txt", ios::app);
ofstream booked ("booked.txt", ios ::app);
     if(myfile.is_open())
{
    while(!myfile.eof())
    {
        getline(myfile,line);
        if((offset=line.find(search,0))!=string :: npos)
        {
            return 1;
        }
        else {
            return 2;
            }
    }
    myfile.close();
}

else
    cout <<"Couldn't open" << endl;

}

Answer 1

You are ending the execution of the function by returning a value in both cases of the if statement. Returning a value will end the execution of the function, so you always end after reading the first line. My guess is you want to move the return 2; to the very end of your function.

Note that this way you also always return without ever calling myfile.close() which might cause problems elsewhere. While I don't understand the meaning of your return values 1 and 2, I suggest this:

int search(int search_num){    
 string search= to_string(search_num);
 int offset;
 string line ;
 ifstream myfile;
 myfile.open("booked.txt", ios::app);
 int return_value = 2;
 ofstream booked ("booked.txt", ios ::app);
 if(myfile.is_open()) {
    while(!myfile.eof()) {
        getline(myfile,line);
        if((offset=line.find(search,0))!=string :: npos) {
            return_value = 1;
            break;
        }
    }
    myfile.close();
 } else {
    cout <<"Couldn't open" << endl;
 }
 return return_value;
}