How to Write a Fortran Program to Sum Numbers in Multiple Result Files?

[kouhei]

Homework Statement

Hello.

A student came to me by yesterday with a question like this:

Here is a sample file (sample.dat),

1 0
2 0
3 0
4 0
5 0
6 0
7 0
8 0
9 0
10 0

and also with many result files, such as result_1.dat:

1 0.1
2 0.2
3 0.3

or result_2.dat

1 0
5 10
9 0.3
10 20

The student would like to write a fortran to sum numbers at the second column. (so if we take only two result files, the final 'result' will be:)

1 0.1
2 0.2
3 0.3
4 0
5 10
6 0
7 0
8 0
9 0.3
10 20

I tried to solve this question but it doesn't work well, so far my program looks like this:

program Main
implicit none

integer GetFileN,ios,nmax1,nmax2
character(160) filename,tmp
integer i,j,m,n
integer x(1:20),a(1:20)
real y,b
integer summ

filename='result_'
print*, 'Please enter the number of files:'
read*,n
do m=1,n
write(tmp,*)m

open(1,file=trim(filename)//trim(adjustl(tmp))
1//'.dat',status='old' )
nmax1=GetFileN(1)
do i = 1,nmax1
read(1,*,iostat=ios) x(i),y
if(ios /=0) then
exit
endif
c write(6,*) x(i),y

open(10,file='sample.dat',status='old')
nmax2=GetFileN(10)
do j=1,nmax2
read(10,*,iostat=ios)a(j),b
if(ios/=0) then
exit
endif
c write(6,*)a(j),b

summ=0
if (any(x==a)) then
summ=b+y
else
summ=b
endif
open(11,status='unknown',file='meanlifetime.dat')
write(11,*)a(j),summ
enddo
enddo
enddo
close(1)
close(10)
close(11)
end

integer function GetFileN(iFileUnit)
implicit none
logical , parameter :: b = .True.
integer , intent( IN ) :: iFileUnit
character*(1) :: c
GetFileN = 0
rewind( iFileUnit )
do while (b)
read( iFileUnit , * ,end =999 ,Err = 999 )c
GetFileN = GetFileN + 1
end Do
999 rewind( iFileUnit )
return
end function GetFileN

Does anyone have an idea?

 

[Valkarie]

Homework Equations N/AThe Attempt at a SolutionThis question can be solved by using an array to store the values from both files. The program should read in the values from the sample.dat file and store them in an array. Then it should loop through the result files one by one and for each result file, it should go through each value in the array and check if the value from the result file matches the value from the sample file. If it does, then the program should add the result file value to the array value. After all the result files have been processed, the program should print out the new array.