option nolet 
print "******************************************"
print "* find local max,min ,version 1.0        *"
print "* peter.vlasschaert@gmail.com,12/01/2018 *"
print "******************************************"
print
!*************************************************
! info : 
! local max : before min ,after min
! global max : max value in the range.

! local min : before max ,after max
! global min : min value in the range.
!**************************************************
rem : excel version see, youtube: Mohammed Mohammed
dim a(1,1)
! range 3 to 7 => values 25,74,92,75,18
nu = 5         ! number values in the range
mat redim a(nu,2)
! read data matrix 'a'
for j=1 to 2
    for i=1 to nu
        read a(i,j) 
    next i
next j
print " range ", " value "
print
mat print a
! find local max ,column ,see : info see above.
rem  : 'first point' in the range can't be local 'max' or 'min'.
rem  :  search for values in the second column of 'a'
!  column vector b , length = nu
dim b(1,1)
mat redim b(nu,2)
! algo : local max, first column of b => ' > if '
for i=2 to nu-1
  if a(i,2) > a(i-1,2) and a(i,2) > a(i+1,2) then
     b(i,1) = a(i,2)
  else
     b(i,1) = 0
  end if
next i
! algo : local min, second column of b => ' <if '
for i=2 to nu-1
  if a(i,2) < a(i-1,2) and a(i,2) < a(i+1,2) then
     b(i,2) = a(i,2)
  else
     b(i,2) = 0
  end if
next i
print "local max (range)";" local min (range)"
print
mat print b
! How to find max in the range.
print
print "*********************************"
print " find max and min two numbers => "
print "*********************************"
print
print " max(2,5) = ", max(2,5)
print " min(2,5) = ", min(2,5)
! algo : Max of the range. 'if  < ' 
for i=1 to nu-1
 if a(i,2) < a(i+1,2) then
    rmax = max(a(i,2),a(i+1,2)) 
 end if 
next i
!******************************
! analog max,min, function exit
!******************************
! algo : Min of the range. 'if > '
for i=1 to nu-1
 if a(i,2) >  a(i+1,2) then
    rmin = min(a(i,2),a(i+1,2)) 
 end if 
next i
print
print "*******************************"
print " global max ,min of a range => "
print "*******************************"
print
print " max value of the range => "; rmax
print " min value of the range => "; rmin
data 3,4,5,6,7
data 25,74,92,75,18
end