Loops/Nested: Difference between revisions

=={{header|Lambdatalk}}==

<lang scheme>

1) a function returning random numbers in [0,20]

{def rn {lambda {} {round {* 20 {random}}}}}

-> rn

2) a random array

{def random_array

{A.new {A.new {rn} {rn} {rn} {rn}}

{A.new {rn} {rn} {rn} {rn}}

{A.new {rn} {rn} {rn} {rn}}

{A.new {rn} {rn} {rn} {rn}}

{A.new {rn} {rn} {rn} {rn}}}}

-> random_array

{random_array}

-> [[12,19,19,18],[14,13,5,4],[2,6,16,12],[11,12,9,8],[18,8,17,9]]

3) a function scanning a row and returning true as soon as the value is found

{def find.row

{lambda {:val :arr :flag}

{if {A.empty? :arr}

then :flag

else {if {= {A.first :arr} :val}

then {find.row :val {A.new} true}

else {find.row :val {A.rest :arr} :flag}} }}}

-> find.row

4) the main function returning the array's items until the value is found, or not

{def find

{def find.rec

{lambda {:val :arr :flag}

{if {A.empty? :arr}

then {if :flag

then :val was found!

else :val was not found.}

else {let { {:val :val} {:arr :arr} {:flag :flag} }

{if {find.row :val {A.first :arr} false}

then {A.first :arr} {find.rec :val {A.new} true}

else {A.first :arr} {find.rec :val {A.rest :arr} :flag}} }}}}

{lambda {:val :arr}

{find.rec :val :arr false}}}

-> find

{find 5 {random_array}}

-> [12,19,19,18] [14,13,5,4] 5 was found!

{find 15 {random_array}}

-> [12,19,19,18] [14,13,5,4] [2,6,16,12] [11,12,9,8] [18,8,17,9] 15 was not found.

</lang>