# include # include # include # include # include # include "bicycle_lock.h" /******************************************************************************/ int bicycle_lock ( int c ) /******************************************************************************/ /* Purpose: BICYCLE_LOCK finds the combination on a typical bicycle lock. Licensing: This code is distributed under the GNU LGPL license. Modified: 13 May 2012 Author: John Burkardt Parameters: Input, int C, the combination, a value between 0 and 999. Output, int BICYCLE_LOCK, the step on which the combination was found. A value of -1 means the combination was not found. */ { int a; int step; step = -1; for ( a = 0; a <= 999; a++ ) { if ( a == c ) { step = a + 1; break; } } return step; } /******************************************************************************/ int get_seed ( ) /******************************************************************************/ /* Purpose: GET_SEED returns a random seed for the random number generator. Licensing: This code is distributed under the GNU LGPL license. Modified: 17 November 2004 Author: John Burkardt Parameters: Output, int GET_SEED, a random seed value. */ { time_t clock; int i4_huge = 2147483647; int ihour; int imin; int isec; int seed; struct tm *lt; time_t tloc; /* If the internal seed is 0, generate a value based on the time. */ clock = time ( &tloc ); lt = localtime ( &clock ); /* Hours is 1, 2, ..., 12. */ ihour = lt->tm_hour; if ( 12 < ihour ) { ihour = ihour - 12; } /* Move Hours to 0, 1, ..., 11 */ ihour = ihour - 1; imin = lt->tm_min; isec = lt->tm_sec; seed = isec + 60 * ( imin + 60 * ihour ); /* We want values in [1,43200], not [0,43199]. */ seed = seed + 1; /* Remap SEED from [1,43200] to [1,Huge]. */ seed = ( int ) ( ( ( double ) seed ) * ( ( double ) i4_huge ) / ( 60.0 * 60.0 * 12.0 ) ); /* Never use a seed of 0. */ if ( seed == 0 ) { seed = 1; } return seed; } /******************************************************************************/ int i4_power ( int i, int j ) /******************************************************************************/ /* Purpose: I4_POWER returns the value of I^J. Licensing: This code is distributed under the GNU LGPL license. Modified: 23 October 2007 Author: John Burkardt Parameters: Input, int I, J, the base and the power. J should be nonnegative. Output, int I4_POWER, the value of I^J. */ { int k; int value; if ( j < 0 ) { if ( i == 1 ) { value = 1; } else if ( i == 0 ) { fprintf ( stderr, "\n" ); fprintf ( stderr, "I4_POWER - Fatal error!\n" ); fprintf ( stderr, " I^J requested, with I = 0 and J negative.\n" ); exit ( 1 ); } else { value = 0; } } else if ( j == 0 ) { if ( i == 0 ) { fprintf ( stderr, "\n" ); fprintf ( stderr, "I4_POWER - Fatal error!\n" ); fprintf ( stderr, " I^J requested, with I = 0 and J = 0.\n" ); exit ( 1 ); } else { value = 1; } } else if ( j == 1 ) { value = i; } else { value = 1; for ( k = 1; k <= j; k++ ) { value = value * i; } } return value; } /******************************************************************************/ int i4_uniform_ab ( int a, int b, int *seed ) /******************************************************************************/ /* Purpose: I4_UNIFORM_AB returns a scaled pseudorandom I4 between A and B. Discussion: The pseudorandom number should be uniformly distributed between A and B. Licensing: This code is distributed under the GNU LGPL license. Modified: 24 May 2012 Author: John Burkardt Reference: Paul Bratley, Bennett Fox, Linus Schrage, A Guide to Simulation, Second Edition, Springer, 1987, ISBN: 0387964673, LC: QA76.9.C65.B73. Bennett Fox, Algorithm 647: Implementation and Relative Efficiency of Quasirandom Sequence Generators, ACM Transactions on Mathematical Software, Volume 12, Number 4, December 1986, pages 362-376. Pierre L'Ecuyer, Random Number Generation, in Handbook of Simulation, edited by Jerry Banks, Wiley, 1998, ISBN: 0471134031, LC: T57.62.H37. Peter Lewis, Allen Goodman, James Miller, A Pseudo-Random Number Generator for the System/360, IBM Systems Journal, Volume 8, Number 2, 1969, pages 136-143. Parameters: Input, int A, B, the limits of the interval. Input/output, int *SEED, the "seed" value, which should NOT be 0. On output, SEED has been updated. Output, int I4_UNIFORM_AB, a number between A and B. */ { int c; const int i4_huge = 2147483647; int k; float r; int value; if ( *seed == 0 ) { fprintf ( stderr, "\n" ); fprintf ( stderr, "I4_UNIFORM_AB - Fatal error!\n" ); fprintf ( stderr, " Input value of SEED = 0.\n" ); exit ( 1 ); } /* Guaranteee A <= B. */ if ( b < a ) { c = a; a = b; b = c; } k = *seed / 127773; *seed = 16807 * ( *seed - k * 127773 ) - k * 2836; if ( *seed < 0 ) { *seed = *seed + i4_huge; } r = ( float ) ( *seed ) * 4.656612875E-10; /* Scale R to lie between A-0.5 and B+0.5. */ r = ( 1.0 - r ) * ( ( float ) ( a ) - 0.5 ) + r * ( ( float ) ( b ) + 0.5 ); /* Round R to the nearest integer. */ value = round ( r ); /* Guarantee that A <= VALUE <= B. */ if ( value < a ) { value = a; } if ( b < value ) { value = b; } return value; } /******************************************************************************/ void timestamp ( ) /******************************************************************************/ /* Purpose: TIMESTAMP prints the current YMDHMS date as a time stamp. Example: 31 May 2001 09:45:54 AM Licensing: This code is distributed under the GNU LGPL license. Modified: 24 September 2003 Author: John Burkardt Parameters: None */ { # define TIME_SIZE 40 static char time_buffer[TIME_SIZE]; const struct tm *tm; time_t now; now = time ( NULL ); tm = localtime ( &now ); strftime ( time_buffer, TIME_SIZE, "%d %B %Y %I:%M:%S %p", tm ); fprintf ( stdout, "%s\n", time_buffer ); return; # undef TIME_SIZE }