Password checker program basically checks if a password is valid or not based on the password policies mention below:
- Password should not contain any space.
- Password should contain at least one digit(0-9).
- Password length should be between 8 to 15 characters.
- Password should contain at least one lowercase letter(a-z).
- Password should contain at least one uppercase letter(A-Z).
- Password should contain at least one special character ( @, #, %, &, !, $, etc...).
Example:
Input: GeeksForGeeks Output: Invalid Password! This input contains lowercase as well as uppercase letters but does not contain digits and special characters. Input: Geek$ForGeeks7 Output: Valid Password This input satisfies all password policies mentioned above.
Approach:
In this program,
- we are using String contains () method to check the passwords. This method accepts a CharSequence as an argument and returns true if the argument is present in a string otherwise returns false.
- Firstly the length of the password has to be checked then whether it contains uppercase, lowercase, digits and special characters.
- If all of them are present then the method isValid(String password) returns true.
Below is the implementation of the above approach:
// C++ code to validate a password
#include<bits/stdc++.h>
using namespace std;
// A utility function to check
// whether a password is valid or not
bool isValid(string password)
{
// For checking if password length
// is between 8 and 15
if (!((password.length() >= 8) &&
(password.length() <= 15)))
return false;
// To check space
if (password.find(" ") !=
std::string::npos)
return false;
if (true)
{
int count = 0;
// Check digits from 0 to 9
for(int i = 0; i <= 9; i++)
{
// To convert int to string
string str1 = to_string(i);
if (password.find(str1) !=
std::string::npos)
count = 1;
}
if (count == 0)
return false;
}
// For special characters
if (!((password.find("@") != std::string::npos) ||
(password.find("#") != std::string::npos) ||
(password.find("!") != std::string::npos) ||
(password.find("~") != std::string::npos) ||
(password.find("$") != std::string::npos) ||
(password.find("%") != std::string::npos) ||
(password.find("^") != std::string::npos) ||
(password.find("&") != std::string::npos) ||
(password.find("*") != std::string::npos) ||
(password.find("(") != std::string::npos) ||
(password.find(")") != std::string::npos) ||
(password.find("-") != std::string::npos) ||
(password.find("+") != std::string::npos) ||
(password.find("/") != std::string::npos) ||
(password.find(":") != std::string::npos) ||
(password.find(".") != std::string::npos) ||
(password.find(",") != std::string::npos) ||
(password.find("<") != std::string::npos) ||
(password.find(">") != std::string::npos) ||
(password.find("?") != std::string::npos) ||
(password.find("|") != std::string::npos)))
return false;
if (true)
{
int count = 0;
// Checking capital letters
for(int i = 65; i <= 90; i++)
{
// Type casting
char c = (char)i;
string str1(1, c);
if (password.find(str1) !=
std::string::npos)
count = 1;
}
if (count == 0)
return false;
}
if (true)
{
int count = 0;
// Checking small letters
for(int i = 97; i <= 122; i++)
{
// Type casting
char c = (char)i;
string str1(1, c);
if (password.find(str1) !=
std::string::npos)
count = 1;
}
if (count == 0)
return false;
}
// If all conditions fails
return true;
}
// Driver code
int main()
{
string password1 = "GeeksForGeeks";
if (isValid(password1))
cout << "Valid Password" << endl;
else
cout << "Invalid Password" << endl;
string password2 = "Geek$ForGeeks7";
if (isValid(password2))
cout << "Valid Password" << endl;
else
cout << "Invalid Password" << endl;
}
// This code is contributed by Yash_R
// Java code to validate a password
public class PasswordValidator {
// A utility function to check
// whether a password is valid or not
public static boolean isValid(String password)
{
// for checking if password length
// is between 8 and 15
if (!((password.length() >= 8)
&& (password.length() <= 15))) {
return false;
}
// to check space
if (password.contains(" ")) {
return false;
}
if (true) {
int count = 0;
// check digits from 0 to 9
for (int i = 0; i <= 9; i++) {
// to convert int to string
String str1 = Integer.toString(i);
if (password.contains(str1)) {
count = 1;
}
}
if (count == 0) {
return false;
}
}
// for special characters
if (!(password.contains("@") || password.contains("#")
|| password.contains("!") || password.contains("~")
|| password.contains("$") || password.contains("%")
|| password.contains("^") || password.contains("&")
|| password.contains("*") || password.contains("(")
|| password.contains(")") || password.contains("-")
|| password.contains("+") || password.contains("/")
|| password.contains(":") || password.contains(".")
|| password.contains(", ") || password.contains("<")
|| password.contains(">") || password.contains("?")
|| password.contains("|"))) {
return false;
}
if (true) {
int count = 0;
// checking capital letters
for (int i = 65; i <= 90; i++) {
// type casting
char c = (char)i;
String str1 = Character.toString(c);
if (password.contains(str1)) {
count = 1;
}
}
if (count == 0) {
return false;
}
}
if (true) {
int count = 0;
// checking small letters
for (int i = 97; i <= 122; i++) {
// type casting
char c = (char)i;
String str1 = Character.toString(c);
if (password.contains(str1)) {
count = 1;
}
}
if (count == 0) {
return false;
}
}
// if all conditions fails
return true;
}
// Driver code
public static void main(String[] args)
{
String password1 = "GeeksForGeeks";
if (isValid(password1)) {
System.out.println(password1 + " - Valid Password");
}
else {
System.out.println(password1 + " - Invalid Password!");
}
String password2 = "Geek$ForGeeks7";
if (isValid(password2)) {
System.out.println(password2 + " - Valid Password");
}
else {
System.out.println(password2 + " - Invalid Password!");
}
}
}
# Python3 code to validate a password
# A utility function to check
# whether a password is valid or not
def isValid(password):
# for checking if password length
# is between 8 and 15
if (len(password) < 8 or len(password) > 15):
return False
# to check space
if (" " in password):
return False
if (True):
count = 0
# check digits from 0 to 9
arr = ['0', '1', '2', '3',
'4', '5', '6', '7', '8', '9']
for i in password:
if i in arr:
count = 1
break
if count == 0:
return False
# for special characters
if True:
count = 0
arr = ['@', '#','!','~','$','%','^',
'&','*','(',',','-','+','/',
':','.',',','<','>','?','|']
for i in password:
if i in arr:
count = 1
break
if count == 0:
return False
if True:
count = 0
# checking capital letters
for i in range(65, 91):
if chr(i) in password:
count = 1
if (count == 0):
return False
if (True):
count = 0
# checking small letters
for i in range(97, 123):
if chr(i) in password:
count = 1
if (count == 0):
return False
# if all conditions fails
return True
# Driver code
password1 = "GeeksForGeeks"
if (isValid([i for i in password1])):
print("Valid Password")
else:
print("Invalid Password!!!")
password2 = "Geek$ForGeeks7"
if (isValid([i for i in password2])):
print("Valid Password")
else:
print("Invalid Password!!!")
# This code is contributed by mohit kumar 29
// C# code to validate a password
using System;
class PasswordValidator
{
// A utility function to check
// whether a password is valid or not
public static bool isValid(String password)
{
// for checking if password length
// is between 8 and 15
if (!((password.Length >= 8)
&& (password.Length <= 15)))
{
return false;
}
// to check space
if (password.Contains(" "))
{
return false;
}
if (true)
{
int count = 0;
// check digits from 0 to 9
for (int i = 0; i <= 9; i++)
{
// to convert int to string
String str1 = i.ToString();
if (password.Contains(str1))
{
count = 1;
}
}
if (count == 0)
{
return false;
}
}
// for special characters
if (!(password.Contains("@") || password.Contains("#")
|| password.Contains("!") || password.Contains("~")
|| password.Contains("$") || password.Contains("%")
|| password.Contains("^") || password.Contains("&")
|| password.Contains("*") || password.Contains("(")
|| password.Contains(")") || password.Contains("-")
|| password.Contains("+") || password.Contains("/")
|| password.Contains(":") || password.Contains(".")
|| password.Contains(", ") || password.Contains("<")
|| password.Contains(">") || password.Contains("?")
|| password.Contains("|")))
{
return false;
}
if (true)
{
int count = 0;
// checking capital letters
for (int i = 65; i <= 90; i++)
{
// type casting
char c = (char)i;
String str1 = c.ToString();
if (password.Contains(str1))
{
count = 1;
}
}
if (count == 0)
{
return false;
}
}
if (true)
{
int count = 0;
// checking small letters
for (int i = 97; i <= 122; i++)
{
// type casting
char c = (char)i;
String str1 = c.ToString();
if (password.Contains(str1))
{
count = 1;
}
}
if (count == 0)
{
return false;
}
}
// if all conditions fails
return true;
}
// Driver code
public static void Main(String[] args)
{
String password1 = "GeeksForGeeks";
if (isValid(password1))
{
Console.WriteLine("Valid Password");
}
else
{
Console.WriteLine("Invalid Password!!!");
}
String password2 = "Geek$ForGeeks7";
if (isValid(password2))
{
Console.WriteLine("Valid Password");
}
else
{
Console.WriteLine("Invalid Password!!!");
}
}
}
// This code is contributed by Rajput-Ji
function isValidPassword(password) {
// for checking if password length is between 8 and 15
if (!(password.length >= 8 && password.length <= 15)) {
return false;
}
// to check space
if (password.indexOf(" ") !== -1) {
return false;
}
// for digits from 0 to 9
let count = 0;
for (let i = 0; i <= 9; i++) {
if (password.indexOf(i) !== -1) {
count = 1;
}
}
if (count === 0) {
return false;
}
// for special characters
if (!/[!@#$%^&*()_+\-=\[\]{};':"\\|,.<>\/?]/.test(password)) {
return false;
}
// for capital letters
count = 0;
for (let i = 65; i <= 90; i++) {
if (password.indexOf(String.fromCharCode(i)) !== -1) {
count = 1;
}
}
if (count === 0) {
return false;
}
// for small letters
count = 0;
for (let i = 97; i <= 122; i++) {
if (password.indexOf(String.fromCharCode(i)) !== -1) {
count = 1;
}
}
if (count === 0) {
return false;
}
// if all conditions fail
return true;
}
// example usage
const password1 = "GeeksForGeeks";
if (isValidPassword(password1)) {
console.log(`${password1} - Valid Password`);
} else {
console.log(`${password1} - Invalid Password!`);
}
const password2 = "Geek$ForGeeks7";
if (isValidPassword(password2)) {
console.log(`${password2} - Valid Password`);
} else {
console.log(`${password2} - Invalid Password!`);
}
Output
GeeksForGeeks - Invalid Password! Geek$ForGeeks7 - Valid Password
