Variable Declaration

This program demonstrates different variable types in Fortran: integers, real numbers (floating-point), and characters.

Variable Types

• integer: Whole numbers
• real(dp): Double precision floating-point numbers
• character(len=20): Character strings of specified length

Double Precision

The integer, parameter :: dp = kind(1.0d0) statement defines a kind parameter for double precision. This ensures consistent precision across the program. Variables declared as real(dp) use double precision, and literals use the _dp suffix (e.g., 1.5_dp).

Implementation

program variable_declaration
    implicit none
    integer, parameter :: dp = kind(1.0d0)
    integer :: int_var
    real(dp) :: real_var
    character(len=20) :: char_var

    int_var = 1
    real_var = 1.5_dp
    char_var = 'a'

    print *, "Integer: ", int_var
    print *, "Real (dp): ", real_var
    print *, "Character: ", char_var
end program variable_declaration

Output

Integer:            1
Real (dp):    1.5000000000000000
Character: a