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c++cunordered-mapbucketunordered-set

stl unordered_set how to set initial bucket count


For an unordered_map i set the initial bucket count by this:

unordered_map<string, dictionaryWord> dictionary(17749); // set initial bucket count to 17749

This way does not seem to work for unordered_set.

/*line 150*/ unsigned char mask;
/*line 151*/ unordered_set<QueryID> query_id(109); // set initial bucket count to 109

Compiler error = 1) expected identifier before numeric constant. 2) expected ‘,’ or ‘...’ before numeric constant. And goes on with a bunch of errors

How to do the same thing for an unordered_set?

Thank you.

=================================================

There are no errors if i remove "(109)"

"/usr/bin/make" -f nbproject/Makefile-Release.mk QMAKE= SUBPROJECTS= .clean-conf
make[1]: Entering directory `/home/petros/NetBeansProjects/ACM_test'
rm -f -r build/Release
rm -f dist/Release/GNU-Linux-x86/acm_test
make[1]: Leaving directory `/home/petros/NetBeansProjects/ACM_test'


CLEAN SUCCESSFUL (total time: 80ms)

"/usr/bin/make" -f nbproject/Makefile-Release.mk QMAKE= SUBPROJECTS= .build-conf
make[1]: Entering directory `/home/petros/NetBeansProjects/ACM_test'
"/usr/bin/make"  -f nbproject/Makefile-Release.mk dist/Release/GNU-Linux-x86/acm_test
make[2]: Entering directory `/home/petros/NetBeansProjects/ACM_test'
mkdir -p build/Release/GNU-Linux-x86/ref_impl
rm -f build/Release/GNU-Linux-x86/ref_impl/core.o.d
g++ -pthread -O3 -std=c++11   -c -O2 -pthread -O3 -std=c++11 -MMD -MP -MF build/Release/GNU-Linux-x86/ref_impl/core.o.d -o build/Release/GNU-Linux-x86/ref_impl/core.o ref_impl/core.cpp
ref_impl/core.cpp:151:37: error: expected identifier before numeric constant
ref_impl/core.cpp:151:37: error: expected ‘,’ or ‘...’ before numeric constant
ref_impl/core.cpp: In function ‘ErrorCode StartQuery(QueryID, const char*, MatchType, unsigned int)’:
ref_impl/core.cpp:250:24: error: expected unqualified-id before ‘(’ token
ref_impl/core.cpp:250:38: error: missing template arguments before ‘)’ token
ref_impl/core.cpp:250:39: error: expected ‘;’ before ‘query_id’
ref_impl/core.cpp:257:19: error: ‘query.SameQueries::query_id’ does not have class type
ref_impl/core.cpp: In function ‘ErrorCode EndQuery(QueryID)’:
ref_impl/core.cpp:265:44: error: ‘queries.std::vector<_Tp, _Alloc>::operator[]<SameQueries, std::allocator<SameQueries> >(((std::vector<SameQueries>::size_type)i)).SameQueries::query_id’ does not have class type
ref_impl/core.cpp:265:58: error: unable to deduce ‘const auto’ from ‘<expression error>’
ref_impl/core.cpp:266:38: error: ‘queries.std::vector<_Tp, _Alloc>::operator[]<SameQueries, std::allocator<SameQueries> >(((std::vector<SameQueries>::size_type)i)).SameQueries::query_id’ does not have class type
ref_impl/core.cpp:267:32: error: ‘queries.std::vector<_Tp, _Alloc>::operator[]<SameQueries, std::allocator<SameQueries> >(((std::vector<SameQueries>::size_type)i)).SameQueries::query_id’ does not have class type
ref_impl/core.cpp:268:36: error: ‘queries.std::vector<_Tp, _Alloc>::operator[]<SameQueries, std::allocator<SameQueries> >(((std::vector<SameQueries>::size_type)i)).SameQueries::query_id’ does not have class type
ref_impl/core.cpp: In function ‘void* TaskCode(void*)’:
ref_impl/core.cpp:463:41: error: ‘quer.SameQueries::query_id’ does not have class type
ref_impl/core.cpp:463:48: error: unable to deduce ‘auto’ from ‘<expression error>’
ref_impl/core.cpp:463:70: error: ‘quer.SameQueries::query_id’ does not have class type
make[2]: *** [build/Release/GNU-Linux-x86/ref_impl/core.o] Error 1
make[2]: Leaving directory `/home/petros/NetBeansProjects/ACM_test'
make[1]: *** [.build-conf] Error 2
make[1]: Leaving directory `/home/petros/NetBeansProjects/ACM_test'
make: *** [.build-impl] Error 2


BUILD FAILED (exit value 2, total time: 1s)

Solution

  • It was inside a struct. It should have been:

    unordered_set<QueryID> query_id = unordered_set<QueryID>(109);
    

    Thank you