Category : accumulate

Accumulate function in Vector (STL) giving negative sum

     accumulate, c++, stl, vector

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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Using accumulate and reduce with any type of execution policy produces large error for huge number of data

     accumulate, c++, execution, reduce, rounding

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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Why can’t I use istream_view and std::accumulate to sum up my input?

     accumulate, c++, c++20, std-ranges

This program: #include <ranges> #include <numeric> #include <iostream> int main() { auto rng = std::ranges::istream_view<int>(std::cin); std::cout << std::accumulate(std::ranges::begin(rng), std::ranges::end(rng), 0); } is supposed to sum up all integers appearing as text on the standard input stream. But – it doesn’t compile. I know std::ranges::begin() and std::ranges::end() exist, so what’s going on? The compiler tells me ..

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