CSC 117 Programming for Scientists and Engineers

Project 8 Due: Wednesday, August 14, 2002

Finding the Maximum of Every Column of an Array

40 points

Write a Fortran 90 program that reads a 2-dimensional array from an input file and computes the maximum of every column.

• The input file will consist of not more than 1000 lines. Each line will be a string of digits of some length between 1 and 80. All lines will have the same length.A small example.
• The input file represents a 2-dimensional array of integers, where each integer takes four columns. For instance, the array presented by the small example has 3 rows and 6 columns, and the first row is (1234,5678,9012,3456,7890,1237).
• Read the first line of the input file into a character variable, and use the instrinsic functions TRIM and LEN to determine how many columns the array should have. The read the first row of the array from the character variable, using it as an internal file.
• Read the rest of the input file into the other rows of the two-dimensional array, using IOSTAT to detect the end of the file.
  Each line of the input file contains one row of the array.
• Write a subroutine whose dummy arguments are assumed-shape arrays. The first argument should be a two-dimensional (in) array, and the second argument should be a one-dimensional (out) array, whose length is equal to the number of columns of the other argument.
  This subroutine should set each entry of its second argument equal to the maximum entry of the corresponding column of its first argument.
• Call the subarray to obtain the maximum value of each column of your two-dimensional array. You will need to use the subarray construction.
• Here is a possible output file you might get from the small input file.
• Here is a big input file.