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  1. #include <stdio.h>
  2.  
  3. typedef long MYenum;
  4.  
  5. enum {
  6. 	SINGLES,
  7. 	PAIRS,
  8. 	TRIPLES,
  9. };
  10.  
  11. int *array = NULL;
  12.  
  13. /* mimic the call to glVertexAttribPointer */
  14. void array_pointer(void *p)
  15. {
  16. 	array = p;
  17. }
  18.  
  19. /* mimicks the behavior of glDrawArrays */
  20. void print_arrays(MYenum mode, int first, size_t count)
  21. {
  22. 	size_t N, i, j;
  23.  
  24. 	if( !array ) return;
  25.  
  26. 	switch(mode) {
  27. 	default: return;
  28.  
  29. 	case SINGLES: N = 1; break;
  30. 	case PAIRS:   N = 2; break;
  31. 	case TRIPLES: N = 3; break;
  32. 	}
  33.  
  34. 	for(i = 0; i <= count-N;) {
  35. 		printf("(");
  36. 		for(j = 0; j < N; ++j, ++i) {
  37.  
  38. 			printf("%d", array[ first + i ] );
  39.  
  40. 			if( j + 1 < N ) printf(", ");
  41. 		}
  42. 		printf(")");
  43. 		if( i + 1 <= count-N+1 ) printf(", ");
  44. 	}
  45. 	printf("\n");
  46. }
  47.  
  48. /* mimics the behavior of glDrawElements */
  49. void print_elements(MYenum mode, size_t count, int const *indices)
  50. {
  51. 	size_t N, i, j;
  52.  
  53. 	if( !array 
  54. 	 || !indices ) return;
  55.  
  56. 	switch(mode) {
  57. 	default: return;
  58.  
  59. 	case SINGLES: N = 1; break;
  60. 	case PAIRS:   N = 2; break;
  61. 	case TRIPLES: N = 3; break;
  62. 	}
  63.  
  64. 	for(i = 0; i <= count-N;) {
  65. 		printf("(");
  66. 		for(j = 0; j < N; ++j, ++i) {
  67.  
  68. 			printf("%d", array[ indices[i] ] );
  69.  
  70. 			if( j + 1 < N ) printf(", ");
  71. 		}
  72. 		printf(")");
  73. 		if( i + 1 <= count-N+1 ) printf(", ");
  74. 	}
  75. 	printf("\n");
  76. }
  77.  
  78. int main(int argc, char *argv[])
  79. {
  80. 	int singles[4] = {
  81. 		11,
  82. 		12,
  83. 		13,
  84. 		14
  85. 	};
  86. 	int single_elements[10] = {
  87. 		0, 1, 0, 2, 3,
  88. 		3, 0, 0, 2, 1
  89. 	};
  90.  
  91. 	int pairs[6] = {
  92. 		21, 22,
  93. 		31, 32,
  94. 		41, 42
  95. 	};
  96. 	int pairs_elements[12] = {
  97. 		0, 1,
  98. 		0, 2,
  99. 		2, 3,
  100. 		2, 4,
  101. 		4, 5,
  102. 		4, 0
  103. 	};
  104.  
  105. 	int triples[9] = {
  106. 		51, 52, 53,
  107. 		61, 62, 63,
  108. 		71, 72, 73
  109. 	};
  110. 	int triple_elements[15] = {
  111. 		0, 1, 2,
  112. 		3, 4, 5,
  113. 		6, 7, 8,
  114. 		7, 4, 1,
  115. 		0, 3, 6
  116. 	};
  117.  
  118. 	printf("== a few chains of singles ==\n");
  119. 	array_pointer(singles);
  120. 	printf("print array starting with 0, 3 consecutive elements:\n");
  121. 	print_arrays(SINGLES, 0, 3);
  122. 	printf("print array starting with 1, 3 consecutive elements:\n");
  123. 	print_arrays(SINGLES, 1, 3);
  124. 	printf("print 10 elements by index:\n");
  125. 	print_elements(SINGLES, 10, single_elements);
  126.  
  127. 	printf("\n== a few chains of pairs ==\n");
  128. 	array_pointer(pairs);
  129. 	printf("print array starting with 0, 6 consecutive elements:\n");
  130. 	print_arrays(PAIRS, 0, 6);
  131. 	printf("print array starting with 1, 3 consecutive elements (should drop one element at the end since 3%%2 = 1):\n");
  132. 	print_arrays(PAIRS, 1, 3);
  133. 	printf("print 12 elements by index:\n");
  134. 	print_elements(PAIRS, 12, pairs_elements);
  135.  
  136. 	printf("\n== a few chains of triples ==\n");
  137. 	array_pointer(triples);
  138. 	printf("print array starting with 0, 9 consecutive elements:\n");
  139. 	print_arrays(TRIPLES, 0, 9);
  140. 	printf("print array starting with 2, 6 consecutive elements:\n");
  141. 	print_arrays(TRIPLES, 2, 6);
  142. 	printf("print 15 elements by index:\n");
  143. 	print_elements(TRIPLES, 15, triple_elements);
  144.  
  145. 	return 0;
  146. }
  147.  
Success #stdin #stdout 0s 2008KB
comments (?)
stdin 
Standard input is empty
stdout 
== a few chains of singles ==
print array starting with 0, 3 consecutive elements:
(11), (12), (13)
print array starting with 1, 3 consecutive elements:
(12), (13), (14)
print 10 elements by index:
(11), (12), (11), (13), (14), (14), (11), (11), (13), (12)

== a few chains of pairs ==
print array starting with 0, 6 consecutive elements:
(21, 22), (31, 32), (41, 42)
print array starting with 1, 3 consecutive elements (should drop one element at the end since 3%2 = 1):
(22, 31)
print 12 elements by index:
(21, 22), (21, 31), (31, 32), (31, 41), (41, 42), (41, 21)

== a few chains of triples ==
print array starting with 0, 9 consecutive elements:
(51, 52, 53), (61, 62, 63), (71, 72, 73)
print array starting with 2, 6 consecutive elements:
(53, 61, 62), (63, 71, 72)
print 15 elements by index:
(51, 52, 53), (61, 62, 63), (71, 72, 73), (72, 62, 52), (51, 61, 71)
https://ideone.com/9JSqFk
language:
C (gcc 8.3)
created:
9 years ago
visibility:
public

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