Validation of password please help

**blueeyes** · 06-30-2019

program should validate the input data (password) based on the following rules: The password length should have a minimum length of 6 and maximum of 15 characters Some characters aren’t allowed in the password including “space” and “-”. If user includesthese two characters in the input, the program should display “invalid password”.

Code:

int main()
{
  char password[15];
  int lenght;

  int str;
  printf("Please enter the password:\n");
  printf("note:no space or - in password\n");
  printf("note:min password lenght =6 and max password lenght =15\n");
  fgets(password, 15, stdin);
  int i = strlen(password);

  if (i < 5 || i > 14) {
    printf("please check the lenght rules ");

  }

  else if (i > 0) {
    for (int j = 0; j <= i; j++) {
      password[j] == ' ';
      password[j] == '-';

    }
    printf("No space is allowed or any hypens - ,please try again");
  } else

    printf("registered");

}

**Salem** · 06-30-2019

Some points.
1. To read 15 characters with fgets(), you need a buffer of 17 chars. You need the +2 for the "\n\0" that's also stored.

2. Try something like if ( password[j] == ' ' )

3. Put the relevant part of the code in a while loop, along the lines of

Code:

int passwordValid = 0;
while ( !passwordValid ) {
    // input
    // checking
    //....
    passwordValid = 1;  // do this when ALL your checks pass.
}

**blueeyes** · 06-30-2019

Code:

/*im doing something wrong ? im new to it */

#include <stdio.h>
#include<string.h>


int main()
{
    char password[17];
   int lenght;
   int passwordValid = 0;


  
   int str;
    
    while ( !passwordValid ) 
    { 
      
      printf("Please enter the password:\n");
    printf("note:no space or - in password\n");
     printf("note:min password lenght =6 and max password lenght =15\n");
    fgets(password,15,stdin);
     int i= strlen(password);
     if(i<5 || i>14) 
      {
        printf("please check the lenght rules ");
      
      }
      
     else if(password[i]=' ')
      {
        
        printf("No space is allowed or any hypens - ,please try again");
      }
      
      else if(password[i]='-')
      {
        
        printf("No space is allowed or any hypens - ,please try again");
      }
        else
        {
          printf("registered");
        }
          passwordValid = 1;
    }  
     
}

**sahnisaxena** · 06-30-2019

Try to change the size of an array by +2, in this way you can able to validate password.

**flp1969** · 06-30-2019

Take a look at strpbrk().

**Salem** · 06-30-2019

1. You need a for loop to check each character.

2. You managed to slip from using == for comparison to using =

**christop** · 07-01-2019

Note that fgets() keeps the linefeed ('\n') character at the end of the string. You can easily remove that with this line of code after fgets():

Code:

password[strcspn(password, "\n")] = '\0';

Also, why do you compare the password's length with 5 and 14? If I entered the password "123456789012345", for example, your code will reject that password, even though it's valid according to the given rules.

Lastly, I hope you know that this is just a programming exercise and that you don't think that this sort of password validation is good practice. A password should be allowed to be longer than 15 characters, and many good passwords contain spaces or other "special" characters. Some of my passwords are longer than 20 characters and contain spaces.

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