Return to rand CVS log

Up to [MW Coherent from dump] / coherent / a / usr / man / ALL

Annotation of coherent/a/usr/man/ALL/rand, revision 1.1

1.1     ! root        1: 
        !             2: 
        !             3: rand()                   General Function                  rand()
        !             4: 
        !             5: 
        !             6: 
        !             7: 
        !             8: Generate pseudo-random numbers
        !             9: 
        !            10: int rand()
        !            11: 
        !            12: rand generates  a set of  pseudo-random numbers.  It  returns in-
        !            13: tegers in the range 0 to  32,767, and purportedly has a period of
        !            14: 2^32.  rand will always  return the same series of random numbers
        !            15: unless you  first call the function srand  to change rand's seed,
        !            16: or beginning-point.
        !            17: 
        !            18: ***** Example *****
        !            19: 
        !            20: This example demonstrates  the functions rand and srand.  It uses
        !            21: a threshold level  that is passed in argv[1] (default, MAXVAL/2),
        !            22: the number  of trials passed  in argv[2] (default,  1,000), and a
        !            23: seed passed in argv[3] (default, no seeding).
        !            24: 
        !            25: 
        !            26: #define MAXVAL 32767    /* range of rand: [0,2^15-1] */
        !            27: 
        !            28: 
        !            29: 
        !            30: main(argc, argv)
        !            31: int argc; char *argv[];
        !            32: {
        !            33:         register int i, hits, threshold, ntrials;
        !            34: 
        !            35: 
        !            36: 
        !            37:         hits = 0;
        !            38:         threshold = (argc > 1) ? atoi(argv[1]) : MAXVAL/2;
        !            39:         ntrials = (argc > 2) ? atoi(argv[2]) : 1000;
        !            40:         if (argc > 3)
        !            41:                 srand(atoi(argv[3]));
        !            42: 
        !            43: 
        !            44: 
        !            45:         for (i = 1; i <= ntrials; i++)
        !            46:                 if (rand() > threshold)
        !            47:                         ++hits;
        !            48: 
        !            49: 
        !            50: 
        !            51:         printf("%d values above %d in %d trials (%D%%).\n",
        !            52:                 hits, threshold, ntrials, (100L*hits)/ntrials);
        !            53: }
        !            54: 
        !            55: 
        !            56: ***** See Also *****
        !            57: 
        !            58: general functions, srand()
        !            59: _T_h_e _A_r_t _o_f _C_o_m_p_u_t_e_r _P_r_o_g_r_a_m_m_i_n_g, vol. 2
        !            60: 
        !            61: 
        !            62: 
        !            63: 
        !            64: COHERENT Lexicon                                           Page 1
        !            65: 
        !            66: 

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.