NAME

factor, primes − factor a number, generate large primes

SYNOPSIS

factor [ number ]

primes [ number ]

DESCRIPTION

When factor is invoked without an argument, it waits for a number to be typed in.  If you type a positive number less than231−1 (about2.1×109), it will factor the number and print its prime factors; each one is printed the proper amount of times.  Then it waits for another number.  It exits if it encounters a zero or any non-numeric character. 

If factor is invoked with an argument, it factors the number as above and then exits. 

Maximum time to factorn is proportional to√n and occurs whenn is prime or the square of a prime. 

When primes is invoked without an argument, it waits for a number to be typed in.  If you type in a number less than, it will print all the primes greater than this number. 

If primes is invoked with an argument, it produces the prime numbers as described above and then exits. 

DIAGNOSTICS

‘Ouch.’ for input out of range or garbage input. 

7th Edition