Variable Assignment

To assign a variable a "value" (the value could be an integer, real, or imaginary number, as well as logical or character) and works similarly to how you would write something mathematically. For example, if we want a variable called a to equal 5, then the variable assignment is written as follows

a = 5

Or we can assign a variable (e.g., area) to be equal to an equation. For example, we may assign

area = length*width

which is an abstract equation that will take the values assigned to length and width and multiply them together to calculate the area. In order of this equation to be used in our program we would need to first assign values to length and width.

Another way to think of a variable is giving a value an alias in the computer code, so you can refer back to it later (or change its value, compute a new value, etc.).

Assigning character variables require you to know its length. For example, if we defined the variable fname with

CHARACTER*5 fname

It will only store five characters when you go to assign the variable. So if we were to assign the value "kevin" to fname we would retain all five letters, but if we were to try and assign "matthew" the variable value would only retain the first five characters and the actual variable value would be matth. For example, the following program

      PROGRAM names

      implicit none
      character*5 fname

      fname = 'matthew'

      print *, "My name is ", fname

      END

would yield the following output

My name is matth