test.cpp

#include <bits/stdc++.h>
// #include <conio.h>

using namespace std;

int main()
{
    char a[30];
    cout << "################################\n";
    cout << " Password - Strength Calculator\n";
    cout << "               ~TheAbhi97\n";
    cout << "################################\n\n";
    cout << "Input a Password : ";
    cin >> a;
    int characters = 0, uppercase = 0, lowercase = 0, digit = 0, middigit = 0, len = 0;
    for (int k = 0; a[k]; k++)
        len++;
    characters = len * 4;
    for (int k = 0; k < len; k++)
    {
        if (a[k] >= 'A' && a[k] <= 'Z')
            uppercase++;
        if (a[k] >= 'a' && a[k] <= 'z')
            lowercase++;
        if (a[k] >= '0' && a[k] <= '9')
            digit++;
    }
    for (int k = 1; k < len - 1; k++)
        if (a[k] >= '0' && a[k] <= '9')
            middigit++;
    uppercase *= 2;
    lowercase *= 2;
    digit *= 4;
    middigit *= 2;
    int gained = characters + uppercase + lowercase + digit + middigit, p = 1, q = 1;
    for (int k = 0; k < len && p == 1; k++)
    {
        if ((a[k] >= 'a' && a[k] <= 'z') || (a[k] >= 'A' && a[k] <= 'Z'))
            p = 1;
        else
            p = 0;
    }
    for (int k = 0; k < len && q == 1; k++)
    {
        if (a[k] >= '0' && a[k] <= '9')
            q = 1;
        else
            q = 0;
    }
    int onlydigchar = 0;
    if (q == 1 || p == 1)
        onlydigchar = len;
    int conschar = 0, up = 0, low = 0;
    for (int k = 0; k < len; k++)
    {
        if (a[k] >= 'A' && a[k] <= 'Z')
        {
            up++;
            if (low == 1)
                low = 0;
            else
            {
                conschar += low;
                low = 0;
            }
        }
        else if (a[k] >= 'a' && a[k] <= 'z')
        {
            low++;
            if (up == 1)
                up = 0;
            else
            {
                conschar += up;
                up = 0;
            }
        }
    }
    if (low == 1 || up == 1)
        low = up = 0;
    conschar += up + low;
    int repeatchar[30] = {0}, d = 0, repeattimes = 0;
    for (int k = 0; k < len; k++)
    {
        d = 0;
        for (int n = 0; n < len; n++)
        {
            if (a[k] == a[n])
                d++;
        }
        if (d == 1 || d == 0)
            repeatchar[k] = 0;
        else if (d > 1)
            repeatchar[k] = 1;
    }
    for (int k = 0; k < len; k++)
        repeattimes += repeatchar[k];
    int sequ = 0, s = 1;
    for (int k = 1; k < len; k++)
    {
        if (a[k - 1] + 1 == a[k])
            s++;
        else
        {
            if (s > 1)
            {
                sequ += s;
            }
            s = 1;
        }
    }
    if (s > 1)
        sequ += s;
    int penalty = onlydigchar + (repeattimes + conschar + sequ) * 2;

    long lwCase = 0;
    long upCase = 0;
    long num = 0;
    long special = 0;
    for (auto ch : a)
    {
        if (isupper(ch))
        {
            upCase = 26;
        }
        else if (islower(ch))
        {
            lwCase = 26;
        }
        else if (isdigit(ch))
        {
            num = 10;
        }
        else
        {
            special = 33;
        }
    }

    double entr = (log2(lwCase + upCase + num + special) * len);

    double result = entr + gained/penalty - penalty;
    if (result < 0)
        result = 0;
    cout << "\n\n\nPassword Strength is " << result << endl;
    if (result <= 45)
        cout << "Password is WEAK.\n";
    else if (result <= 85)
        cout << "Password is MODERATE.\n";
    else if (result <= 120)
        cout << "Password is STRONG.\n";
    else
        cout << "Password is VERY STRONG.\n";
    // getch();
    return 0;
}