如题，比如TXT里面是123
                   1234
                   12345
把123先读出来 然后在吧1234读出来

用回车换行符判断结束标志

fstream infile("itemlist.txt", ios::in);

     int Size = 0;
     string temp;
     string item1[100];
     while( !infile.eof() ){
        getline(infile, temp);
            item1[Size] = temp;
            Size++;
            }// done reading file
     infile.close();
            
     for(int i = 0; i < Size; i++){
            cout<<i+1<<". "<<item1[i]<<endl;
             }

直接getline函数即可