fork download
copy 
  1. /*********************************************************//**
  2.  * Author:		migf1
  3.  * from Book:		C Programming, A Modern Approach (2nd edition)
  4.  * Chapter: 		8 (Arrays)
  5.  * Programming project: 9 (page 179)
  6.  ************************************************************/
  7.  
  8. #include <stdio.h>
  9. #include <stdlib.h>
  10. #include <string.h>
  11. #include <time.h>
  12.  
  13. #define UNAVAIL			-1				/* flag unavailable pos */
  14.  
  15. #define NROWS			10				/* table height in rows */
  16. #define NCOLS			10				/* table width in cols  */
  17.  
  18. #define myMIN(x,y)		( (x) < (y) ? (x) : (y) )
  19.  
  20. #define ROW(pos)		( (pos) / NCOLS )		/* calc row-index of pos*/
  21. #define COL(pos)		( (pos) % NCOLS )		/* calc col-index of pos*/
  22.  
  23. #define POSUP(pos)		( (pos) - NCOLS )		/* calc pos minus 1 row */
  24. #define POSDN(pos)		( (pos) + NCOLS )		/* calc pos plus 1 row  */
  25. #define POSLF(pos)		( (pos) - 1 )			/* calc pos minus 1 col */
  26. #define POSRT(pos)		( (pos) + 1 )			/* calc pos plus 1 col  */
  27.  
  28. #define EMPTY			'.'				/* empty cells' content */
  29. #define USED			"ABCDEFGHIJKLMNOPQRSTUVWXYZ"	/* used cells' contents */
  30.  
  31. #define ISEMPTY(pos, tab)	( EMPTY == (tab)[ (pos) ] )	/* is tab[pos] empty?   */
  32.  
  33. #define ISBLOCKED(pos, tab)							\
  34. 	( ROW(pos) == 0 || !ISEMPTY( POSUP(pos), tab ) )			\
  35. 	&& ( ROW(pos) == NROWS-1 || !ISEMPTY( POSDN(pos), tab ) )		\
  36. 	&& ( COL(pos) == 0 || !ISEMPTY( POSLF(pos), tab ) )			\
  37. 	&& ( COL(pos) == NCOLS-1 || !ISEMPTY( POSRT(pos), tab ) )
  38.  
  39. enum Dir { UP=0, DN, LF, RT };					/* allowed mv directions*/
  40.  
  41. /*********************************************************//**
  42.  * Print the contents of the board.
  43.  ************************************************************/
  44. void tab_print( const char tab[] )
  45. {
  46. 	for (int n=0; n < NROWS * NCOLS; n++)
  47. 	{
  48. 		if ( n != 0 && n % NCOLS == 0 )
  49. 			putchar('\n');
  50. 		printf( "%c ", tab[n] );
  51. 	}
  52.  
  53. 	putchar('\n');
  54. }
  55.  
  56. /*********************************************************//**
  57.  * ** UNUSED **
  58.  * The macro: ISBLOCKED() is used instead, but it has not been debuged thoroughly yet.
  59.  * In case of problems, try using this function instead of the macro.
  60.  ************************************************************/
  61. _Bool isblocked( const int pos, const char tab[] )
  62. {
  63. 	int nblocked = 0;
  64.  
  65. 	if ( ROW(pos) == 0  || !ISEMPTY(POSUP(pos), tab) )
  66. 		nblocked++;
  67. 	if ( ROW(pos) == NROWS-1 || !ISEMPTY(POSDN(pos), tab) )
  68. 		nblocked++;
  69. 	if ( COL(pos) == 0 || !ISEMPTY(POSLF(pos), tab) )
  70. 		nblocked++;
  71. 	if ( COL(pos) == NCOLS-1 || !ISEMPTY(POSRT(pos), tab) )
  72. 		nblocked++;
  73.  
  74. //printf("%c: nblocked = %d\n", tab[pos], nblocked );
  75. 	return 4 == nblocked;
  76. }
  77.  
  78.  
  79. /*********************************************************//**
  80.  * Calc a new position in table tab, according to current position pos & direction dir.
  81.  * Return the newlly calculated position, or UNAVAIL on error.
  82.  ************************************************************/
  83. int get_nextpos( const int pos, const enum Dir dir, const char tab[] )
  84. {
  85. 	int ret = UNAVAIL;
  86.  
  87. 	switch (dir)
  88. 	{
  89. 		case UP:
  90. 			ret = 	ROW(pos) > 0 && ISEMPTY( POSUP(pos), tab )
  91. 				? POSUP(pos)
  92. 				: UNAVAIL;
  93. 			break;
  94.  
  95. 		case DN:
  96. 			ret 	= ROW(pos) < NROWS-1 && ISEMPTY( POSDN(pos), tab )
  97. 				? POSDN(pos)
  98. 				: UNAVAIL;
  99. 			break;
  100. 		case LF:
  101.  
  102. 			ret = 	COL(pos) > 0 && ISEMPTY( POSLF(pos), tab )
  103. 				? POSLF(pos)
  104. 				: UNAVAIL;
  105. 			break;
  106.  
  107. 		case RT:
  108. 			ret 	= COL(pos) < NCOLS-1 && ISEMPTY( POSRT(pos), tab )
  109. 				? POSRT(pos)
  110. 				: UNAVAIL;
  111. 			break;
  112. 		default:
  113. 			break;
  114. 	}
  115.  
  116. 	return ret;
  117. }
  118.  
  119. /*********************************************************//**
  120.  *
  121.  ************************************************************/
  122. int main( void )
  123. {
  124. 							/* total # of moves allowed     */
  125. 	const int 	MVTOTAL = myMIN( NROWS*NCOLS, (int)(strlen(USED) - 1) );
  126. 	int 		mvcount = 0;			/* moves counter                */
  127. 	int 		pos = 0, try = 0;		/* current & next move positions*/
  128. 	char 		tab[ NROWS * NCOLS ];		/* our un-initialized board     */
  129.  
  130. 	srand( (unsigned)time(NULL) );			/* init pseudo-random seed      */
  131. 	memset( tab, EMPTY, sizeof(tab) );		/* init table with dots         */
  132.  
  133. 	tab[0] 	= USED[0];				/* start with filled 1st pos    */
  134. 	while ( mvcount < MVTOTAL )
  135. 	{
  136. 		/* a blocked pos terminates the loop */
  137. 		if ( ISBLOCKED(pos, tab) )
  138. 			break;
  139.  
  140. 		/* try moves until an available pos is found */
  141. 		do
  142. 			try = get_nextpos( pos, rand() % 4, tab );
  143. 		while ( UNAVAIL == try );
  144.  
  145. 		/* accept available move as next pos */
  146. 		pos = try;
  147. 		tab[ pos ] = USED[ ++mvcount ];
  148. 	}
  149. 	tab_print( tab );
  150.  
  151. 	exit( EXIT_SUCCESS );
  152. }
  153.  
Success #stdin #stdout 0.01s 1720KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
A . . . . . . . . . 
B Y Z . . . . . . . 
C X W V . . . . . . 
D E . U . . . . . . 
G F . T . . . . . . 
H . . S . . . . . . 
I . . R Q . . . . . 
J K N O P . . . . . 
. L M . . . . . . . 
. . . . . . . . . .
https://ideone.com/5bsaB
language:
C99 (gcc 8.3)
created:
13 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!