Variables

To represent data whose value may change within our program we use variables.

• In Fortran 90 a variable is represented by a name consisting of up to 31 alphanumeric characters plus '_'. (Example: Temperature, Density, Area, Radius, string1, t3)
• The first character must be a letter.
• The letters may be either case, but beware as 'a' is the same as 'A'.
• Tips:
  • Choose good/useful names (e.g. maxval, minval instead of i1,i2)
  • Avoid using names of keywords (e.g. ``If'' ``Integer'') as variable names.
  • Do not use '_' as the first character of a variable name.