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  1. #include <cmath>
  2. #include <initializer_list>
  3.  
  4. #include <vector>
  5. #include <string>
  6. #include <iostream>
  7. using namespace std;
  8.  
  9. class CycledIndexer{
  10.     using Number = int;
  11. public:
  12.     CycledIndexer(Number max_val, Number val):
  13.         max_value(max_val), value(fixed(val)){}
  14. public:
  15.     Number max() const{ return max_value; }
  16.     void update_max(Number max){
  17.         max_value = max;
  18.         value = fixed(value);
  19.     }
  20.  
  21.     void add(int val){ value = fixed(value + val); }
  22.     void sub(int val){ add(-val); }
  23.  
  24.     void set(int val){ value = fixed(val); }
  25.  
  26.     CycledIndexer operator+(Number num){ return CycledIndexer(max_value, value + num); }
  27.     CycledIndexer operator-(Number num){ return CycledIndexer(max_value, value - num); }
  28.  
  29.     CycledIndexer &operator=(Number num){
  30.         set(num);
  31.         return *this;
  32.     }
  33.  
  34.     CycledIndexer &operator+=(Number num){
  35.         add(num);
  36.         return *this;
  37.     }
  38.     CycledIndexer &operator-=(Number num){
  39.         sub(num);
  40.         return *this;
  41.     }
  42.  
  43.     CycledIndexer &operator++(){
  44.         add(1);
  45.         return *this;
  46.     }
  47.     CycledIndexer &operator--(){
  48.         sub(1);
  49.         return *this;
  50.     }
  51.  
  52.     CycledIndexer operator++(int){
  53.         auto result = *this;
  54.         add(1);
  55.         return result;
  56.     }
  57.     CycledIndexer operator--(int){
  58.         auto result = *this;
  59.         sub(1);
  60.         return result;
  61.     }
  62.  
  63.     operator Number() const
  64.     { return value; }
  65. private:
  66.     Number fixed(Number val){
  67.         auto mod = val%max_value;
  68.         return mod<0 ? max_value + mod : mod;
  69.     }
  70. private:
  71.     Number max_value, value;
  72. };
  73.  
  74. int main(){
  75. 	vector<string> strings = { "Ala", "ma", "kota", ",", "a", "kot", "ma", "Ale", "." };
  76. 	CycledIndexer indexer(strings.size(), 0);
  77.  
  78. 	auto test = [&](auto desc, auto func){
  79. 		cout << desc << endl;
  80. 		indexer = 0;
  81. 		for(size_t i = 0; i < 20; ++i){
  82. 			const auto &text = strings.at(func());
  83. 			cout << text << (text == "."? "\n" : " ");
  84. 		}
  85. 		cout << endl;
  86. 	};
  87.  
  88. 	test("(indexer++)", [&]{ return indexer++; });
  89. 	test("(++indexer)", [&]{ return ++indexer; });
  90. 	test("(indexer--)", [&]{ return indexer--; });
  91. 	test("(--indexer)", [&]{ return --indexer; });
  92. }
Success #stdin #stdout 0s 3416KB
comments (?)
stdin
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Standard input is empty
stdout
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(indexer++)
Ala ma kota , a kot ma Ale .
Ala ma kota , a kot ma Ale .
Ala ma 
(++indexer)
ma kota , a kot ma Ale .
Ala ma kota , a kot ma Ale .
Ala ma kota 
(indexer--)
Ala .
Ale ma kot a , kota ma Ala .
Ale ma kot a , kota ma Ala .

(--indexer)
.
Ale ma kot a , kota ma Ala .
Ale ma kot a , kota ma Ala .
Ale
https://ideone.com/C7KLH3
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

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