varsity college 2

Variable Assignment

• When assigning a value to a variable:

  • The variable must be on the left-hand side of the operator.

Declaring Constants

• Name Constants:

  • Similar to variables, but they can only be assigned a value once.

  • Should be assigned a meaningful name corresponding to a value that will not change during the program's execution.

• Magic Number:

  • An unnamed constant that can lead to confusion, thus it's better to use named constants.

Example of Constants

• Example given: num_sales_tax_rate = 0.06

  • Variable name: num_sales_tax_rate (it is a noun)

  • This variable is a constant because it is written in capital letters.

Identical Statements

• After declaring sales_tax_rate, both statements:

  1. tax_amount = price * 0.06

  2. tax_amount = price * sales_tax_rate

  • These two statements have identical meanings because sales_tax_rate represents the constant value of 0.06.

  • Using the constant makes the code cleaner and easier to maintain as it avoids magic numbers.

Identifying Variables

1. First Variable: Check for validity:

   • Is it correct? No.

     • Why? Because it contains a space between words.

2. Second Variable: Check for validity:

   • Is it correct? No.

     • Why? Contains special characters which are not allowed in variable names.

• Importance of properly named variables to ensure readability and prevent errors in programming.