# COUNTPRIMES --- count primes in an interval  

  # Use counprimes(2,100) to count the number
  # of primes in the interval [a,b].


  countprimes := proc(a,b)
     local i, N;
     N := 0;
     for i from a to b do
        if isprime(i) 
          then N := N + 1;
        fi;
     od;
     RETURN( N );
  end:


  # jac, 6/10/2001