How to find out the maximum cumulative value?

UNIX for Beginners Q & A
1

I have a file has thousands of rows and each row has a number and the number can be positive or negative. I want to do the cumulative sum from the first row. How can I find out the maximum cumulative value when I do the sum work row by row. Here is the example:

4
-3
2
-3
-1
1

In this case, the maximum cumulative value is 3 which is from adding the first 3 rows numbers (4, -3 and 2)
Thank you very much

2

Is this a homework assignment? Homework and coursework questions can only be posted in the homework and coursework forum with a completely filled out questionnaire from the homework rules.

If this is homework, please refile in the proper forum with a completely filled out template. If it is not homework, please explain what the purpose is for this problem.

And why do you think the maximum cumulative value is 3 when the accumulated value after reading the first line is 4?

What code have you tried to solve this problem?

What shell and operating system are you using?

3

This is not homework or assignment. I am doing some accounting work (many transaction) to report the highest balance on the banking account and the bank statement didn't provide the cumulative balance number to me, so I have to figure out a way to find it.
The reason I didn't count the first row because the adding work doesn't start. I don't do code work so I posted a help on this forum probably I posted the wrong place. Sorry.

4

Would this do?

awk '{print $1, SUM+=$1}' file3
4 4
-3 1
2 3
-3 0
-1 -1
1 0
5

If you need the cumulative maximum along with the line number where it occurs:

#! /bin/ksh

typeset -i iCurrLine=0
typeset -i iMaxLine=0
typeset -i iMaxSum=0
typeset -i iVal=0
typeset -i iSum=0

while read iVal ; do
     (( iCurrLine += 1 ))
     (( iSum += iVal ))
     if [ $iSum -gt $iMax ] ; then
          iMaxLine=$iCurrLine
          iMaxSum=iSum
     fi
done < /path/to/input

print - "Max Value: $iMaxSum \t occurred in line: $iMaxLine"

exit 0

Should work equally in bash.

I hope this helps.

bakunin

6

I'm afraid I misread your request. How about

awk '{print $1, SUM+=$1, MAX=MAX<SUM?SUM:MAX}' file