Example 1: IMPLICIT: everything is integer:
IMPLICIT INTEGER (A-Z) X = 3 K = 1 STRING = 0
Example 2: Complex if it starts with U, V, or W; character if it starts with C or S:
IMPLICIT COMPLEX (U,V,W), CHARACTER*4 (C,S) U1 = ( 1.0, 3.0) STRING = 'abcd' I = 0 X = 0.0
Example 3: All items must be declared:
IMPLICIT NONE CHARACTER STR*8 INTEGER N REAL Y N = 100 Y = 1.0E5 STR = 'Length'
In the above example, once IMPLICIT NONE is specified in the beginning. All the variables must be declared explicitly.
Example 4: A letter used twice: @
IMPLICIT INTEGER (A-Z) IMPLICIT REAL (A-C) C = 1.5E8 D = 9
In the above example, D through Z implies INTEGER, and A through C implies REAL.