Two dimensional arrays in FORTRAN

A two dimensional array is a table of rows and columns. It must be declared before use, either with a type statement or with DIMENSION.

Syntax

      type name(rows, columns)
      DIMENSION name(rows, columns)

Examples: INTEGER A(3,4) (3 rows, 4 columns, 12 elements) and REAL B(2,2).

• Subscripts start from 1 by default: A(1,1) is the first element. Other bounds can be given as A(0:2, 0:3).
• An element is written A(i,j), row i and column j.
• FORTRAN stores arrays in column-major order (the first subscript changes fastest).
• FORTRAN 77 allows up to seven dimensions.
• The subscripts can be integer expressions, and nested DO loops or nested implied DO are used to process them.

Example: read and print a 2×3 array

      PROGRAM ARR2D
      INTEGER A(2,3), I, J
      READ *, ((A(I,J), J = 1, 3), I = 1, 2)
      DO 10 I = 1, 2
         PRINT *, (A(I,J), J = 1, 3)
   10 CONTINUE
      STOP
      END

For input 1 2 3 4 5 6 it prints 1 2 3 and then 4 5 6.