f_highest(src, len)=>
adj_len = len < 1? 1: len
val = src
for i=0 to (adj_len-1)
val := src[i] >= val ? src[i] : val
return = val
f_lowest(src, len)=>
adj_len = len < 1? 1: len
val = src
for i=0 to (adj_len-1)
val := src[i] <= val ? src[i] : val
return = val