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function aceind=advise(shufvals,p) % This function advises the player as to which card is the ace % It uses the fact that we chose a prime p such that the numerical % value of ace is a quadratic non-residue, while the numerical values % of the other cards are quadratic residues sln=length(shufvals); for j=1:sln, test(j)=powermod(shufvals(j),(p-1)/2,p); end; aceind=find(test~=1); disp(['Ace Index: ', num2str(aceind)]);