c++ - This while loop does its proper function, but required for something else? -


i making hotel reservation program in c++. when user wants open guest's info file, have input first name , surname of guest. if there isn't data file name in it, tells user file doesn't exist. asks again file name, , user inputs real file name.

the problem if inputs file name know real, file doesn't exist. if re-enter file name when prompted, loads file.

by way, loop required file open. that's main thing i'm stumped about. tried messing around see if needed it, , apparently. , need first file_ptr.open(filename,ios::in); , along second. don't understand why need both.

here specific code while loop:

cout << "open member file"; system ("cls"); char filename [100]; ifstream file_ptr; cout << "\n\t\t\t\tsaved members:\n\n"; system ("dir/b *."); cout << "\n\nplease type name of member you\n"; cout << "     wish open appears above or\n"; cout << "     type z (lower case) return main menu: "; cin.ignore(); gets (filename);  if (filename[0]  != 'z') {      //cout<< "\nplease enter 6 digit registration access code: ";     //cin>>rac;      //if (rac == (file_ptr, membershipnumber))     //{            file_ptr.open(filename,ios::in);             // char in_char;            while(!file_ptr)            {               cout << "member not exist\n";               gets (filename);               file_ptr.open(filename,ios::in);             }

i don't understand why while loop required open file if user gave legit file name. says file doesn't exist, opens file on second try.

this output:

saved members:

hunter grad

please type name of member wish open appears above or type z (lower case) return main menu: hunter grad

member not exist

the second time input same file name, takes me file

i don't understand why though? hoping know. thanks

http://www.cplusplus.com/reference/istream/istream/ignore/

you tell input stream ignore 1 character, filename not typed. if typed "john" try open file "ohn".

if had looked @ variable in debugger or checked output, have been obvious. debugger far more effective @ solving problems stackoverflow. want come here when stuck.

the second time type in "john" file named "john", since there no ignore in loop.


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