Algo majuscules/minuscules

Salut a Tous aujourd'hui j'ai un Algorithme de Pascal pour un Programe qui convertir a partir de majuscule vers Minuscule.

voila 1ére Méthode avec / Pour / jusqu'a :

DÉBUT
ecrire "donnez une chaine de caractère"
lire ch
ch1=""
pour i=1 jusqu'a longueur (ch) faire
(selon)selectionner sousensemble (ch,i,1)
"a":ch1=ch1+"A"
"b":ch1=ch1+"B"
.
.
.
"z":ch1=ch1+"Z"
(finselon)finselectionner
finpour
ecrire ch1       
FIN

voila la deuxiéme :

DÉBUT
ecrire "donnez une chaine"
lire ch
ch1=["a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"]
ch2=["A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"]
ch3=""
pour i=1 jusqu'a longueur (ch)faire
pour j=1 jusqu'a longueur (ch1) faire
si sousensemble(ch,i,1)=ch1[j] alors
ch3=ch3+ch2[j]
finsi
finpour
finpour
ecrire ch3
FIN

en attende de la traduction en pascal @++ :D