GetSum is a container code snippet to sum all values in a one-dimensional container. To sum all values in a two-dimensional matrix, go to the GetSum (on matrix) page.
There are multiple ways to perform GetSum:
- The general algorithm way (best)
- The algorithm way on a std::vector<int> (intermediate)
- The for-loop way on a std::vector<int> (worst)
#include <algorithm> #include <numeric> #include <vector> //From http://www.richelbilderbeek.nl/CppGetSum.htm template <class T> const T::value_type GetSum(const T& v) { return std::accumulate(v.begin(), v.end(), static_cast<T::value_type>(0.0)); }
The algorithm way on a std::vector<int>
This version is given as the answer of Exercise #9: No for-loops.
#include <algorithm> #include <numeric> #include <vector> //From http://www.richelbilderbeek.nl/CppGetSum.htm const int GetSum(const std::vector<int>& v) { return std::accumulate(v.begin(),v.end(),0); }
The for-loop way on a std::vector<int>
Prefer algorithms over loops [1,2].
#include <vector> //From http://www.richelbilderbeek.nl/CppGetSum.htm int GetSum(const std::vector<int>& v) { const int sz = static_cast<int>(v.size()); const int sum = 0; for (int i=0; i!=sz; ++i) { sum+=v[i]; } return sum; }
- Bjarne Stroustrup. The C++ Programming Language (3rd edition). ISBN: 0-201-88954-4. Chapter 18.12.1 : 'Prefer algorithms over loops'
- Herb Sutter and Andrei Alexandrescu. C++ coding standards: 101 rules, guidelines, and best practices. ISBN: 0-32-111358-6. Chapter 84: 'Prefer algorithm calls to handwritten loops.'