Two sum: Difference between revisions

</pre>

=={{header|Icon}} and {{header|Unicon}}==

{{Trans|Lua}}

Icon and Unicon are ordinal languages, first index is one.

<tt>fullimag</tt> library used to pretty print lists.

<lang unicon>#

# twosum.icn, find two array elements that add up to a given sum

# Dedicated to the public domain

#

link fullimag

procedure main(arglist)

sum := pop(arglist) | 21

L := []

if *arglist > 0 then every put(L, integer(!arglist)) & L := sort(L)

else L := [0, 2, 11, 19, 90]

write(sum)

write(fullimage(L))

write(fullimage(twosum(sum, L)))

end

# assume sorted list, only interested in zero or one solution

procedure twosum(sum, L)

i := 1

j := *L

while i < j do {

try := L[i] + L[j]

if try = sum then return [i,j]

else

if try < sum then

i +:= 1

else

j -:= 1

}

return []

end</lang>

{{out}}

<pre>$ unicon -s twosum.icn -x

21

[0,2,11,19,90]

[2,4]