Example :

Write pseudocode to validate a given password.

For a password to be valid it must contain:

• at least two lower case letters
• at least two uppercase characters
• at least three digits
• minimum 8 characters long

A function ValidatePassword is needed to check if a given password follows the above rules. This function takes a parameter Pass as a parameter and returns TRUE if it is valid and FALSE otherwise.

FUNCTION ValidatePassword(Pass: STRING) RETURNS BOOLEAN
   DECLARE Result: BOOLEAN
   DECLARE Lcase: INTEGER
   DECLARE Ucase: INTEGER
   DECLARE len: INTEGRER
   DECLARE Letter: CHARACTER

   Lcase ← 0
   Ucase ← 0
   Digits ← 0 
   Len ← LENGTH(Pass)

   FOR x ← 1 TO Len
      Letter ← MID(Pass,x,1)
      IF Letter >= 'A' Letter <= Z THEN
         Ucase ← Ucase + 1
      ELSE IF Letter >= 'a' AND Letter <= 'z' THEN
         Lcase ← Lcase + 1
      ELSE IF Letter >= '0' AND Letter <= '9' THEN
         Digits ← Digits + 1
      ENDIF
   NEXT x

   IF len >= 8 AND Lcase >= 2 AND Ucase >= 2 AND Digits >= 2 THEN
      Result ← True
   ELSE
      Result ← False
   ENDIF
   
   RETURN Result
ENDFUNCTION

Description:
LENGTH() function accepts a string and returns the number of characters in it.
MID(str,x,y) function extracts a substring of length y, from the string str, starting from the position x.    
Pass - The variable which stores the password received by the function.
Letter - stores a character extracted by the MID() function from the string

STACK

sample:

Write pseudocode for implementing stack using array. Write the following procedure for stack operations:

• Push() – Accepts an integer value to be pushed into the stack.
• Pop() – to remove an item from the stack
• and Display() – to display the content of the stack.

Display a menu to choose the stack operations like, Push, Pop, Display and Exit.

DECLARE MyStack: ARRAY[1,5] OF INTEGERS
DECLARE Choice: INTEGER
DECLARE Max: INTEGER
DECLARE Top: INTEGER
DECLARE Bottom: INTEGET
---------
PROCEDURE Push(val : INTEGER)
   IF Top = StackFull THEN
      OUTPUT "Sorry, Stack Full"
   ELSE
      Top ← Top + 1
      MyStack[Top] ← Val
   ENDIF
ENDPROCEDURE
---------
PROCEDURE Display()
   IF Top = 0 THEN
      OUTPUT "Stack is Empty"
   ELSE
      ind ← Top
      WHILE ind > 0
         OUTPUT MyStack[ind]
         ind ← ind - 1        
   ENDIF   
ENDPROCEDURE
---------
ROCEDURE Pop()
   IF Top < 1 THEN
      OUTPUT "Stack is Empty!"
   ELSE
      OUTPUT MyStack[Top],"has been removed from stack"
      Top ← Top - 1
      IF Top = 0 THEN
         Bottom ← 0
      ENDIF
   ENDIF
ENDPROCEDURE
---------

StackFull ← 5
Top ← 0
Bottom ← 0
REPEAT
   OUTPUT "1. PUSH"
   OUTPUT "2. POP"
   OUTPUT "3. DISPLAY"
   OUTPUT "4. EXIT"
   OUTPUT "Enter your choice"
   INPUT choice

   CASE Choice OF
      1: 
         OUTPUT "Enter a number to push"
         INPUT num
         Push(num)

      2: Pop()

      3: Display()
   ENDCASE
UNTIL Choice = 4