You should clean up your test statements... This is my preferred style of writing conditionals:
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//.........
if (choice == 1) {
main();
} elseif (choice == 2) {
cout << "\tThank you for using this Program :) ";
} else {
cout << "Invalid Choice :( \n\nYou are terminated to Library Main Menu \n\n";
Library();
}
}
Also, you should never call main! I suggest taking the code from main and putting it in a function, and then calling that function from main and replacing any calls to main with calls to the new function.