euc(u,v,w) /* Evaluates the greatest common factor of u and v */
char *u, *v, *w ;
{       char *i, *j, *a, *z, *malloc() ;
        i = malloc(15) ;
        j = malloc(15) ;
        a = malloc(15) ;
        z = malloc(15) ;
        copy(u,j) ;
        copy(v,i) ;
        if strcmp(u,v) > 0)
        {       copy(u,i) ;
                copy(v,j) ;
        }
        copy(one,a) ;
        while (strcmp(a,xero) > 0 )
        {       copy(i,a) ;
                residue(a,j) ;
                copy(j,z) ;
                copy(a,j) ;
                copy(z,i) ;
        }
        copy(z,w) ;
        if(strcmp(z,one) = 0 ) return(1) ;
        else return(0) ;
}