algorithms-numeric.cpp

#define CATCH_CONFIG_MAIN

#include <array>
#include <functional>

#include "catch.hpp"

using namespace std;

TEST_CASE("partial_sum") {
  vector<int> num{1, 2, 3, 4}, result;
  partial_sum(num.begin(), num.end(), back_inserter(result));
  REQUIRE(result == vector<int>{1, 3, 6, 10});
}

TEST_CASE("adjacent_difference") {
  vector<int> fib{1, 1, 2, 3, 5, 8}, fib_diff;
  adjacent_difference(fib.begin(), fib.end(), back_inserter(fib_diff));
  REQUIRE(fib_diff == vector<int>{1, 0, 1, 1, 2, 3});
}

TEST_CASE("inner_product") {
  vector<int> nums1{1, 2, 3, 4, 5};
  vector<int> nums2{1, 0, -1, 0, 1};
  const auto result =
      inner_product(nums1.begin(), nums1.end(), nums2.begin(), 10);
  REQUIRE(result == 13);
}

TEST_CASE("reduce") {
  vector<int> nums{1, 2, 3};
  const auto result1 = reduce(nums.begin(), nums.end(), -1);
  REQUIRE(result1 == 5);
  const auto result2 = reduce(nums.begin(), nums.end(), 2, multiplies<>());
  REQUIRE(result2 == 12);
}

TEST_CASE("accumulate") {
  vector<int> nums{1, 2, 3};
  const auto result1 = accumulate(nums.begin(), nums.end(), -1);
  REQUIRE(result1 == 5);
  const auto result2 = accumulate(nums.begin(), nums.end(), 2, multiplies<>{});
  REQUIRE(result2 == 12);
}

TEST_CASE("iota") {
  array<int, 3> easy_as;
  iota(easy_as.begin(), easy_as.end(), 1);
  REQUIRE(easy_as == array<int, 3>{1, 2, 3});
}

TEST_CASE("plus") {
  plus<short> adder;
  REQUIRE(3 == adder(1, 2));
  REQUIRE(3 == plus<short>{}(1, 2));
}