Sorts the elements in the range[first, last) in non-descending order. The order of equal elements is not guaranteed to be preserved.

If any of the following conditions is satisfied, the behavior is undefined:

[edit]Parameters

[edit]Complexity

Given\(\scriptsize N\)N aslast- first:

[edit]Exceptions

The overloads with a template parameter namedExecutionPolicy report errors as follows:

• If execution of a function invoked as part of the algorithm throws an exception andExecutionPolicy is one of thestandard policies,std::terminate is called. For any otherExecutionPolicy, the behavior is implementation-defined.
• If the algorithm fails to allocate memory,std::bad_alloc is thrown.

[edit]Possible implementation

See also the implementations inlibstdc++ andlibc++.

[edit]Notes

BeforeLWG713, the complexity requirement allowedsort() to be implemented using onlyQuicksort, which may need\(\scriptsize O(N^2)\)O(N2
) comparisons in the worst case.

Introsort can handle all cases with\(\scriptsize O(N \cdot \log(N))\)O(N·log(N)) comparisons (without incurring additional overhead in the average case), and thus is usually used for implementingsort().

libc++ has not implemented the corrected time complexity requirementuntil LLVM 14.

[edit]Example

#include <algorithm>#include <array>#include <functional>#include <iostream>#include <string_view> int main(){std::array<int,10> s{5,7,4,2,8,6,1,9,0,3}; auto print=[&s](std::string_viewconst rem){for(auto a: s)std::cout<< a<<' ';std::cout<<": "<< rem<<'\n';};     std::sort(s.begin(), s.end());    print("sorted with the default operator<");     std::sort(s.begin(), s.end(),std::greater<int>());    print("sorted with the standard library compare function object"); struct{bool operator()(int a,int b)const{return a< b;}}    customLess;     std::sort(s.begin(), s.end(), customLess);    print("sorted with a custom function object");     std::sort(s.begin(), s.end(),[](int a,int b){return a> b;});    print("sorted with a lambda expression");}

0 1 2 3 4 5 6 7 8 9 : sorted with the default operator<9 8 7 6 5 4 3 2 1 0 : sorted with the standard library compare function object0 1 2 3 4 5 6 7 8 9 : sorted with a custom function object9 8 7 6 5 4 3 2 1 0 : sorted with a lambda expression

[edit]Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

[edit]See also

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