Add library/cmake task

passwords.cpp

@@ -0,0 +1,34 @@
+#include "passwords.h"
+
+int possible_combinations( int characters, int length )
+{
+    if( characters <= 0 || length <=0 )
+        return 0;
+
+    return pow( characters, length );
+}
+
+bool good_password( std::string password )
+{
+    int upper = 0, lower = 0, special = 0, digit = 0;
+    const int goodThreshold = 1000000000;
+
+    // count types of characters in password
+    for( char c : password )
+    {
+        if     ( c >= 'A' && c <= 'Z' ) ++upper;    // is uppercase character
+        else if( c >= 'a' && c <= 'z' ) ++lower;    // is lowercase character
+        else if( c >= '0' && c <= '9' ) ++digit;    // is a number
+        else                            ++special;
+    }
+
+    // how many characters need to be checked
+    int characters = 0;
+    if( upper ) characters += 26;
+    if( lower ) characters += 26;
+    if( digit ) characters += 10;
+    if( special ) characters += 10;
+
+    // good password if possible combinations > threshold
+    return possible_combinations( characters, password.length() ) > goodThreshold;
+}

passwords.h

@@ -0,0 +1,25 @@
+#ifndef LIBARARY_H
+#define LIBRARY_H
+
+#include <math.h>
+#include <string>
+
+/**
+ * Calculate the number of possible passwords for the
+ * given character set and password length
+ * 
+ * @param characters number of different possible characters in the password
+ * @param length password length
+ * @return number of possible passwords
+ */
+int possible_combinations( int characters, int length );
+
+/**
+ * Returns if a given password is a good one
+ * 
+ * @param password the password to test
+ * @return was it a good password
+ */
+bool good_password( std::string password );
+
+#endif

validate.cpp

@@ -0,0 +1,20 @@
+#include "passwords.h"
+
+#include <iostream>
+
+int main()
+{
+    std::string userInput;
+
+    std::cout << "Enter a password to test if it is a good one" << std::endl;
+    std::cout << "  Obviously you shouldn't use a real one: ";
+
+    std::cin >> userInput;
+
+    if( good_password( userInput ) )
+        std::cout << "Good password" << std::endl;
+    else
+        std::cout << "Bad password" << std::endl;    
+
+    return 0;
+}