Essential Books

Deleting values from a set

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The most obvious method, if you just want to reset your set/multiset to an empty one, is to use clear: 

std::set<int> sut;
sut.insert(10);
sut.insert(15);
sut.insert(22);
sut.insert(3); 
sut.clear(); //size of sut is 0

Then the erase method can be used. It offers some possibilities looking somewhat equivalent to the insertion: 

std::set<int> sut;
std::set<int>::iterator it;
          
sut.insert(10);
sut.insert(15);
sut.insert(22);
sut.insert(3); 
sut.insert(30);
sut.insert(33);
sut.insert(45);
    
// Basic deletion
sut.erase(3);
    
// Using iterator
it = sut.find(22);
sut.erase(it);
          
// Deleting a range of values
it = sut.find(33);
sut.erase(it, sut.end());
    
std::cout << std::endl << "Set under test contains:" << std::endl;
for (it = sut.begin(); it != sut.end(); ++it)
{
  std::cout << *it << std::endl;
}

Output will be: 

Set under test contains:                                                                                                                                                                                                                                                                                                  
10                                                                                                                                                                                                                                                                                                                        
15                                                                                                                                                                                                                                                                                                                        
30

All those methods also apply to multiset. Please note that if you ask to delete an element from a multiset, and it is present multiple times, all the equivalent values will be deleted.

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std::set and std::multiset:
* std::set and std:multiset
* Changing the default sort of a set
* Deleting values from a set
* Inserting values in a set
* Inserting values in a multiset
* Searching values in set and multiset
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0 Getting started
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29 std::any
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33 std::function
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35 std::iomanip
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42 Returning multiple values from a function
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102 Attributes
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110 C++ vs. C++ 11 vs C++ 17
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131 Layout of object types
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136 Debugging
137 Futures and promises
138 More undefined behaviors
139 Mutexes
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141 Unit testing
142 decltype
143 Digit separators
144 C++ Containers
145 Arithmetic meta-programming
146 Contributors