Password function and arrays - c++

Question

I'm writing a simple password program, but the else if statement always applies, even if the password is put in correctly. This works fine if I use a single char instead of an array, and change "hotdog" to 'h', and I think it might have something to do with unseen characters, like a space or return. I was sure cin.ignore() took care of return/enter.
Sorry, I'm fairly new to programming.
#include <iostream>
int main()
{
std::cout << "What is the password?\n" << std::endl;
char password[20] = "NULL";
std::cin >> password;
std::cin.ignore();
std::cout << password << " is your entry?\n";
if (password == "hotdog")
{
std::cout << "Correct!";
}
else if (password != "hotdog")
{
std::cout << "Incorrect!";
}
else
{
}
std::cin.get();
}

Answer 1

Firstly, change char password[20] to string password. This prevents a buffer overflow if they type in more than 20, and it enables you to use == for string comparison.
The code std::cin.ignore() ignores a single character. You want to actually ignore the entire remainder of the line. There is no way to ignore "everything else typed so far" because there may have been characters typed which are still buffered. In practice, it works well to treat input as a series of lines.
The most accurate way to ignore the rest of the line is to ignore all characters up to and including '\n', which appears in the input stream at the end of the line (by definition).
std::cin.ignore( std::numeric_limits<std::streamsize>::max(), '\n' );
which may require #include <limits>. Another way is to read a string and discard it:
std::string t;
std::getline( std::cin, t );
NB. Check your understand of if...else . Once you have if ( condition ), then the next else will already get everything that was not in that condition. It's pointless to actually write else if ( !condition ); and your final else { block can never be entered, because the previous two conditions were exhaustive.

Answer 2

The problem is with how you are using the if-else statement. Try this code out:
#include <iostream>
int main()
{
std::cout << "What is the password?\n" << std::endl;
char password[20] = "NULL";
std::cin >> password;
std::cin.ignore();
std::cout << password << " is your entry?\n";
if (stricmp("hotdog", password) == 0)
{
std::cout << "Correct!";
}
else
{
std::cout << "Incorrect!";
}
std::cin.get();
}

Answer 3

When I take your code and compile it, even the term hotdog does not work properly, I obtain the following:
What is the password?
hotdog
hotdog is your entry?
Incorrect!
As suggested above, a string is a better method and works as intended based on your requirements. Here is sample replacement code that works as intended (with this code spaces are allowed, with the other answers, spaces are not, it all depends what is intended):
#include <iostream>
#include <string>
using namespace std;
int main (int argc, char ** argv)
{
cout << "What is the password?\n" << endl;
string password = "NULL";
getline(cin, password);
cout << password.c_str() << " is your entry?\n";
if (password == "hotdog")
{
cout << "Correct!";
}
else if (password != "hotdog")
{
cout << "Incorrect!";
}
else
{
// Added from original; however, this should never occur
cout << "Else?";
}
system("pause");
return 0;
}
Output of Replacement Code
What is the password?
hotdog
hotdog is your entry?
Correct!

Answer 4

You had to use strcmp() function to compare strings properly in c++,so I added the cstring library:
#include <iostream>
#include <cstring>
#include <string>
using namespace std;
int main(){
string password;
cin >> password;
cout << password << " is your entry?\n";
char hd [7] = "hotdog";
if (strcmp(password.c_str(),hd) == 0){
cout << "Correct!\n";
}
else if (strcmp(password.c_str(),hd) != 0){
cout << "Incorrect!\n";
}
else{
cin.get();
}
}