PROGRAMS

void Permute(n) 
{ 
    for i = 1 to 9 
        if B[i]=0     // if i is free 
        { 
            B[i]=1 
            A[n]=i    
            if (n % 3 = 0) // if n is div by 3 
            { 
                if RowSum() = 15 
                { 
                    if n<9 
                        Permute(n+1)    
                    else   // at the end 
                        TestMagic() 
                } 
            } 
            else 
                Permute(n+1) //recurse 
            B[i]=0 
        } 
}