What means for i=a,1,-1 in pseudocode?

Question

I have a code in pseudocode.

This is a line of code: for i=k1,1,-1 do Ti <- Ti-1 + Ti.

k1 is an integer. Ti is an array.

The question is: what means for i=k1,1,-1? I know what is for but I don't know what is i=k1,1,-1.

Thank you!

score 2 · Answer 1 · answered Jul 10 '15 at 05:26

2

It means the loop is counting downwards (-1) starting at k1, finishing at 1.

answered Jul 10 '15 at 05:26

Bathsheba

Amadan · Accepted Answer · 2015-07-10T05:30:12.553

2

Have i assume values from k1 to 1 with steps of -1. Equivalent to C:

for (i = k1; i >= 1; i += -1)

The syntax in your question is basically same as in Fortran, been around for decades:

      DO 10,i=k1,1,-1
      T(i) = T(i-1) + T(i)
10    CONTINUE

edited Jul 10 '15 at 05:30

answered Jul 10 '15 at 05:26

Amadan

score 1 · Answer 3 · answered Jul 10 '15 at 05:26

1

It probably means that i starts at k1 and decreases to 1 by steps of -1 , i.e. in C

for (i=k1; i>=1; i--)

answered Jul 10 '15 at 05:26

3 Answers3