回答編集履歴
4
yumetodoさんからご指摘を受けて
test
CHANGED
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@@ -51,6 +51,34 @@
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}
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```
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修正：yumetodoさんからご指摘を受けて
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---
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今回の場合、[std::next](https://cpprefjp.github.io/reference/iterator/next.html)の方が簡潔に処理を記述できるようです。
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yumetodoさんが書かれたslice_sum関数はこちら。
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> ```C++
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template<typename T>
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int slice_sum(const std::vector<T>& v, size_t from, size_t to) {
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assert(to <= v.size());
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return std::accumulate(std::next(v.cbegin(), from), std::next(v.cbegin(), to), T{});
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}
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> ```
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3
追記
test
CHANGED
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@@ -51,3 +51,79 @@
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}
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```
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コメントを受けて
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---
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構造体を利用する例。
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```C++
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#include <iostream>
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#include <numeric>
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#include <vector>
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struct Person {
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Person(const std::string& name, const std::vector<int>& scores)
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: name_(name), scores_(scores) { }
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auto& get_name(void) const noexcept {
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return this->name_;
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}
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auto& get_scores(void) const noexcept {
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return this->scores_;
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}
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private:
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const std::string& name_;
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const std::vector<int> scores_;
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};
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int main(void) {
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Person p("青木", {2, 3, 4, 5});
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int sum = std::accumulate(
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p.get_scores().cbegin(),
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p.get_scores().cend(),
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0
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);
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std::cout << p.get_name() << " sum : " << sum << std::endl;
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return 0;
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}
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```
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2
assert追加
test
CHANGED
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@@ -1,6 +1,8 @@
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1
1
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[std::advance](https://cpprefjp.github.io/reference/iterator/advance.html)を使うと良いかと思います。
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2
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3
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```C++
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#include <cassert>
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#include <iterator>
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@@ -13,6 +15,10 @@
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int slice_sum(const std::vector<int>& v, size_t from, size_t to) {
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assert(to <= v.size());
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auto it_begin = v.cbegin(), it_end = v.cend();
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1
成形
test
CHANGED
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@@ -40,7 +40,7 @@
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return 0;
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return 0;
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}
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