Category : accumulate

If I use the accumulate function in C++ like the below std::vector<int> v2{1, 2, 3, 4, 5}; int sum = 0; std::cout << std::accumulate(v2.begin(), v2.end()) It will simply sum all the numbers. But I wanted to calculate 1-2+3-4+5 I was thinking of some way to accumulate 1,3,5 and 2,4 separately and then do it But ..

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I have a function which should accumulate all the values in an unordered map: int sum_val(std::unordered_map<char, int> vm){ auto addition = [](int a, std::unordered_map<char, int>::iterator b){ return a + b->second; }; return std::accumulate(vm.begin(), vm.end(), 0, addition); } However, when I try to compile this, I get the following error: error: no matching function for call ..

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When i am coding the code below, i am getting a negative sum (-294967296). #include<iostream> #include<vector> #include<numeric> using namespace std; int main() { vector<long long int> v={1000000000 , 1000000000 , 1000000000 , 1000000000}; cout<<"Sum of all the elements are:"<<endl; cout<<accumulate(v.begin(),v.end(),0); } but when i am coding the code below i am getting a positive sum ..

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The result of the following code is very surprising to me. Why does using accumulate produce such a large error? I know that because it is single precisions, it will have a round-off error but when using reduce without any policy (single precision), this round-off error is not so significant! In fact, round-off errors is ..

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