code(c):={
if (c=="é") return 100;
if (c=="è") return 99;
if (c=="à") return 98;
if (c=="ç") return 97;
if (c=="ù") return 96;
if (c=="ê") return 95;
return(asc(c)-32);
};

decode(k):={
if (k== 100) return "é";
if (k==99) return "è";
if (k==98) return "à";
if (k==97) return "ç";
if (k==96) return "ù";
if (k==95) return "ê";
return(char(k+32));
};

jules_cesar(message,cle):={
local s,j,messcode;
s:=size(message);
messcode:="";
for (j:=0;j<s;j++) {
messcode:=append(messcode,decode(irem(cle+code(message[j]),101)));
}
return (messcode);
};

lineaire(message,cle):={
local s,j,messcode;
s:=size(message);
messcode:="";
for (j:=0;j<s;j++) {
messcode:=messcode+decode(irem(cle*code(message[j]),101));
}
return (messcode);
};