Help with creating a password?

[Whiss00]

Okay so the following program is supposed to decide whether or not a password is correct give that it is;
-No longer than 16 characters
-No shorter than 8 characters.
It contains at least:
-One uppercase letter
-One lowercase letter
-One number
and
-No special characters //(isalnum(name.at()))

My program will label all passwords as incorrect no matter what, it's breaking my C++ beginning heart </3 :(. Please #include<help> //Hashtag include help thanks.
-P.S. I know I don't need a lot returns true and false but it's just to get used to it for now.

#include<iostream>
#include<cstdlib>
#include<string>
using namespace std;

bool isProper(string);

int main()
{
string password;
cout << "Enter a password that contains:"
<< "-No special characters.\n "
<< "-At least 1 upper, 1 lower case letter and 1 number \n"
<< "Between 8 and 16 characters long. \n";
cin >> password;
while(!isProper(password))
{
cout << "Enter a password: ";
cin >> password;
}

cout << "Your password is " << password << endl;

system("PAUSE");
return 0;
}

bool isProper(string password)
{
if((password.length() < 8)||(password.length() > 16))
return false;

for(int i = 0; i < password.length(); i++)
{
if(isdigit(password.at(i)))
return true;
else
return false;
}

for(int i = 0; i < password.length(); i++)
{
if(isdigit(password.at(i)))
return true;
else
return false;
}

for(int i = 0; i < password.length(); i++)
{
if((isdigit(password.at(i)))&&(islower(password.at(i))))
return true;
else
return false;
}

for(int i = 0; i < password.length(); i++)
{
if(!isalnum(password.at(i)))
return true;
else
return false;
}

return true;
}

[xismn]

Your isProper function isn't doing what you think it's doing. I will say that it's returning prematurely. Can you figure out what's wrong by looking at the following example?

#include <iostream>
#include <string>

bool is_proper_string(std::string string) {

	//a string is considered "proper" if it only contains letters (alpha).
	//No digits allowed!

	for (int i = 0; i < string.size(); ++i) {

		if (isalpha(string[i])) {
			return true;
		}
		else {
			return false;
		}

	}

	return false;

}

int main() {

	std::string string = "hello123";

	if (is_proper_string(string)) {
		std::cout << "Proper" << std::endl;
	}
	else {
		std::cout << "Not Proper" << std::endl;
	}

	std::cin.get();
	return 0;
}

The string "hello123" is supposed to be improper, because it contains digits, but this program prints "Proper". What could it be?

[longberns]

@Whiss00, i think your teacher wants you to train more on isupper(), islower(), isalnum()
http://www.cplusplus.com/reference/cctype/

I would prefer to break the program to check every part so that the user can get a friendly error message.

Working code

// program to test a valid password
// created by blongho, 2017-05-16
/*
Conditions
- No longer than 16 characters
- No shorter than 8 characters.
It contains at least :
- One uppercase letter
- One lowercase letter
- One number
and
-No special characters 
*/

#include <iostream>
#include <string>
using namespace std;

// is using find_first_of()
//const string LOWERCASE = "abcdefghijklmnopqrstuvwxyz";
//const string UPPERCASE = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
//const string NUMBERS = "0123456789";

bool isShorter(const string password);		// check lower limit
bool isLonger(const string password);		// check upper limit
bool hasUpperCase(const string password);	  // checks if it has uppercase
bool hasLowerCase(const string password);	// checks if it has lowercase
bool hasNumber(const string password);		// checks that password has a number
bool hasSpecialCharacters(const string password); // checks that it has no special characters
bool checkPassword(const string &password);    // checks all conditions and prints result
void start();  // has all the magic

int main()
{
	start();

	return 0;
}
bool isShorter(const string password)
{
	return password.size() < 8 ? true : false;
	// same as
	/*if (password.size() < 8) // password.size() is same as password.lenght();
	{
	return true;
	}
	return false;*/
}

bool isLonger(const string password)
{
	return password.size() > 16 ? true : false;
}

bool hasUpperCase(const string password)
{
	/*size_t found = password.find_first_of(UPPERCASE);
	if (found != string::npos)
	return true;*/
	// check each character in password
	for (auto &c : password)
	{
		if (isupper(c))
			return true;
	}
	return false;
}

bool hasLowerCase(const string password)
{
	/*size_t found = password.find_first_of(LOWERCASE);
	if (found != string::npos)
	return true;*/

	// check each character in password
	for (auto &c : password)
	{
		if (islower(c))
			return true;
	}
	return false;
}

bool hasNumber(const string password)
{
	/*size_t found = password.find_first_of(NUMBERS);
	if (found != string::npos)
	return true;*/
	// check each character in password
	for (auto &c : password)
	{
		if (isdigit(c))
			return true;
	}
	return false;
}

bool hasSpecialCharacters(const string password)
{
	// check each character in password
	for (auto &c : password)
	{
		if (!isalnum(c))
			return true;
	}
	return false;
}

// check validity of password
bool checkPassword(const string & password)
{
	bool isGood = true;

	if (!isShorter(password) && !isLonger(password) && hasUpperCase(password) 
		&& hasLowerCase(password) && hasNumber(password) && !hasSpecialCharacters(password))
	{
		cout << endl << "Proper password." << endl << endl;
		isGood = true;
	}
	else
	{
		cout << endl << "Improper password! Reason..." << endl;

		if (isShorter(password))
			cout << "Your password is shorter than required (at least 8 characters)." << endl;
		if (isLonger(password))
			cout << "Your password can not be longer than 16 characters." << endl;
		if (!hasUpperCase(password))
			cout << "Your password must have at least one upper case letter." << endl;
		if (!hasLowerCase(password))
			cout << "Your password must have at least one lower case letter." << endl;
		if (!hasNumber(password))
			cout << "Your password must have at least one number." << endl;
		if (hasSpecialCharacters(password))
			cout << "No special characters permitted." << endl;
		isGood = false;
	}
	return isGood;
}

// program starts and ends here
void start()
{
	cout << endl << "Hello this program takes and validates your password" << endl << endl;
	string password;
	
	cout << endl << "Please enter your password: ";
	getline(cin, password);

	// continue asking for password as long as it does not satisfy condition
	while (!checkPassword(password))
	{
		cout << endl << "Try another password: ";
		getline(cin, password);
	}
	
}

http://cpp.sh/4bf2k

[Handy Andy]

Hello Whiss00,

Based on what you started with this is what I came up with:

#include<iostream>
#include<cstdlib>  // <--- Not sure if this is needed.
#include<string>

bool isProper(std::string);

int main()
{
	std::string password{ "" };
	bool good{ false };

	//  Changed the way this is displayed.
	std::cout << "Enter a password that contains:"
		<< "\n-No special characters.\n"
		<< "-At least 1 upper case letter,\n1 lower case letter and \n1 number \n"
		<< "Between 8 and 16 characters long. \n";

	// Not needed because of change to while loop.
	//std::cout << "\nEnter Password: ";

	//std::cin >> password;

	while (!good)
	{
		std::cout << "\n Enter a password: ";
		std::cin >> password;
		good = isProper(password);
	}

	if (good)
		std::cout << "\n Your password is valid." << std::endl;

	std::cout << "\n Your password is " << password << std::endl;
	
	std::cin.get();
	return 0;
}

bool isProper(std::string password)
{
	bool digit{ false };
	bool uppr{ false };
	bool lowr{ false };

	int numDigits{ 0 };
	int numUppr{ 0 };
	int numLowr(0);

	if ((password.length() < 8) || (password.length() > 16))
		return false;

	for (int i = 0; i < password.length(); i++)
	{
		if (isdigit(password.at(i)))
		{
			digit = true;  // <--- Set not return.
			numDigits++;  // <--- May not be used or used later. Just an idea for now.
		}
	}

	if (!digit)
		std::cout << "\n Your password does not contain a number.\n";

	// Other checks here.

	return (digit && lowr && uppr);
}

Hope this helps,

Andy

Edit changed line 35.