Question

Criteria for Passwords

1. At least 8 characters in length.

2. Consist of only letters and digits

3. Have at least 2 digits.

Write C++ code to read from 3 files of at least 10 passwords named passwords_one.txt, passwords_two.txt, passwords_three.txt. Sort the passwords depending on if they fit the criteria listed above. If they do fit the criteria put them in a file named valid_passwords.txt then tell the console how many passwords were sorted into that file. If they don't fit the criteria put them into a folder named invalid_passwords.txt.  The code can only be comprised using <fstream>, <iostream>,  and the <string> header files. DO NOT us break or continue statements in your code!!  

Answer 1

#include<iostream>
#include<fstream>
#include<string>

using namespace std;

//function to test if its a alphanumeric character

bool isLetter(char c){

    if( c >='a' && c<='z' ){
        return true;

    }
    else if(c >='a' && c<='z' ){
        return true;
    }else{
        return false;
    }

}

//function to test if its digit
bool isDigit(char c){

    if( c >='0' && c<='9' ){
        return true;

    }
    else{
        return false;
    }

}

//function to test if its valid password

bool isValid(string s){
    int len = s.length();
    if(len<8)
      return false;
    int countDigit=0; //will count number of digits found
    for(int i=0;i<len;i++){
        char c = s[i];
     
        if( isLetter(c)){

        }else if(isDigit(c)){
            countDigit++;

        }else{
            return false;     // false if neither digit nor letter
        }
    }
    if( countDigit <2)   // no two digits or more
       return false;
    return true;
}

int main(){
ofstream myValidFile;
myValidFile.open("valid_passwords.txt");   //valid password txt
ofstream myInValidFile;
myInValidFile.open("invalid_passwords.txt"); //invalid password

ifstream myReadFile1;
myReadFile2.open("passwords_one.txt");
string str;
if (myReadFile1.is_open()) {
while (std::getline(myReadFile1, str))    //read each line of the text
    {
       if(isValid(str)){                            //check validity
           myValidFile1 << str<<endl;   //add to valid file
       }
       else{
           myInValidFile << str<<endl;       //add to invalid file

       }
    }
    }
ifstream myReadFile2;         //again do the same for second file
myReadFile.open("passwords_two.txt");
string str;
if (myReadFile2.is_open()) {
while (std::getline(myReadFile2, str))
    {
       if(isValid(str)){
           myValidFile << str<<endl;
       }
       else{
           myInValidFile << str<<endl;

       }
    }
    }
ifstream myReadFile3; // again do the same for third file
myReadFile.open("passwords_three.txt");
string str;
if (myReadFile3.is_open()) {
while (std::getline(myReadFile3, str))
    {
       if(isValid(str)){
           myValidFile << str<<endl;
       }
       else{
           myInValidFile << str<<endl;

       }
    }
    }
    myReadFile1.close();    // close all the open files
    myReadFile2.close();
    myReadFile3.close();
    myValidFile.close();
    myInValidFile.close();

    return 0;
}