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  1. #include <regex>
  2. #include <iostream>
  3.  
  4. using namespace std;
  5.  
  6. // types of operators
  7. enum class opType: char { unary, lasso, rasso, none };
  8.  
  9. // operator descriptors
  10. struct opDesc {
  11. 	string symbol;
  12. 	opType type;
  13. 	char   priority;
  14.  
  15. 	// partial order comparison
  16. 	bool operator< (const opDesc& a) const
  17. 	{
  18. 		// unary operators first
  19. 		if (symbol == a.symbol) return type < a.type;
  20. 		return symbol < a.symbol;
  21. 	}
  22.  
  23. 	// comparison with strings
  24. 	static bool comp_desc_str (const opDesc& a, const string& s)
  25. 	{
  26. 		return a.symbol < s;
  27. 	}
  28. 	static bool comp_str_desc (const string& s, const opDesc& a)
  29. 	{
  30. 		return s < a.symbol;
  31. 	}
  32.  
  33. 	// display
  34. 	friend ostream& operator<<(ostream& os, const opDesc& op);
  35. };
  36.  
  37. ostream& operator<<(ostream& os, const opDesc& op)
  38. {
  39.     os << op.symbol << "[" << (int)op.type << ":" << (int)op.priority << "]";
  40.     return os;
  41. }
  42.  
  43. static opDesc op_descriptors[] = {
  44. 	{ "+" , opType::unary, 8 }, // unary +
  45. 	{ "-" , opType::unary, 8 }, // unary -
  46. 	{ "~" , opType::unary, 8 }, // bitwise not
  47. 	{ "**", opType::rasso, 7 }, // power
  48. 	{ "*" , opType::lasso, 6 }, // multiplication
  49. 	{ "/" , opType::lasso, 6 }, // division
  50. 	{ "%" , opType::lasso, 6 }, // remainder
  51. 	{ "+" , opType::lasso, 5 }, // addition
  52. 	{ "-" , opType::lasso, 5 }, // substraction
  53. 	{ "<<", opType::lasso, 4 }, // left shift
  54. 	{ ">>", opType::lasso, 4 }, // right shift
  55. 	{ "&" , opType::lasso, 3 }, // bitwise and
  56. 	{ "^" , opType::lasso, 2 }, // bitwise xor
  57. 	{ "|" , opType::lasso, 1 }, // bitwise or 
  58. 	{ "(" , opType::none , 0 }, // braces
  59. 	{ ")" , opType::none , 0 }
  60. };
  61.  
  62. int main(void)
  63. {
  64. 	// sort descriptors by value and type
  65. 	sort(begin(op_descriptors), end(op_descriptors));
  66.  
  67. 	// do some searches
  68. 	string patterns[] = { "+", "-", ">>", "**" };
  69.  
  70. 	for (string s : patterns)
  71. 	{
  72. 		pair<opDesc*, opDesc*> ops;
  73. 		// this won't work
  74. 		/*
  75. 		ops = equal_range(
  76. 			std::begin(op_descriptors), 
  77. 			std::end  (op_descriptors), 
  78. 			s,
  79. 			opDesc::comp_desc_str or opDesc::comp_str_desc);
  80.         */
  81. 		// this works
  82. 		ops.first = lower_bound(
  83. 			std::begin(op_descriptors), 
  84. 			std::end  (op_descriptors), 
  85. 			s, opDesc::comp_desc_str);
  86. 		ops.second = upper_bound(
  87. 			std::begin(op_descriptors), 
  88. 			std::end  (op_descriptors), 
  89. 			s, opDesc::comp_str_desc);
  90. 		cout << s <<": "<< ops.first[0] << ops.second[-1] << endl;
  91. 	}
  92. }
Success #stdin #stdout 0s 3436KB
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stdin
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Standard input is empty
stdout
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+: +[0:8]+[1:5]
-: -[0:8]-[1:5]
>>: >>[1:4]>>[1:4]
**: **[2:7]**[2:7]
https://ideone.com/CPUAfW
language:
C++14 (gcc 8.3)
created:
11 years ago
visibility:
public

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