while(carac2!=0)
{
carac2 = carac2 + resultat[cpt3] ;
resultat[cpt3] = carac2 % 100 ;
carac2 = carac2 div 100 ;
cpt3++ ;
}


Are you sure you did it well?
carac2 = carac2 div 100 - I'm assuming I see the division, rigth? Then go study math - the division will never give you 0 (in the integers ring) - and you check for 0 in while loop - endless cycle.