How to use sum function in c++

The sum function in C can add the elements in the container and return the result. The specific steps are as follows: Determine the container type, such as vector, list, or array. Gets an iterator pointing to the first element of the container. Use the std::accumulate function, passing in the container type, an iterator, and an initial value (usually 0). The function returns the sum of the elements in the container.

Usage of sum function in C

The sum function in C is a general Type function that adds the elements in a container and returns the result. It accepts two parameters:

• Container type: The type of container to add elements to, such as vector, list or array.
• Container iterator: Iterator pointing to the first element of the container.

Usage syntax:

<code class="cpp">template<typename T, typename Iter>
T sum(Iter begin, Iter end);</code>

Where:

• T is the type of container element.
• Iter is the type of container iterator.

Example:

Use the sum function to sum the elements in a vector<int>:

<code class="cpp">#include <vector>
#include <numeric> // 包含 sum 函数

int main() {
  std::vector<int> numbers = {1, 2, 3, 4, 5};

  int sum_of_numbers = std::accumulate(numbers.begin(), numbers.end(), 0);

  std::cout << "元素的和为：" << sum_of_numbers << std::endl;

  return 0;
}</code>

Output:

<code>元素的和为：15</code>

Notes:

• The container must store elements in order, otherwise The sum function will not sum correctly.
• The container cannot be empty, otherwise the sum function will throw an exception.
• For floating-point types (such as float and double), the sum function may produce small rounding errors.

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