I did that but it gave me all these errors also if I remove that then if I give it a correct password it doesn't say "Thank you, that is a valid password."
int main()
{
char userinput[1024];
do
{
cout << "Please enter a password:\n";
cin >> userinput;
} while(!verify_chars(userinput));
cout << "Thank you, that is a valid password.\n";
return 0;
}