测试_第14章_STL算法.cpp

← 测试总览 · 目录

编译运行：clang++ -std=c++26 -Wall -Wextra -pthread 测试_第14章_STL算法.cpp -o t && ./t（需先 cd 测试/）

// 第14章测试：STL 算法
#include <print>
#include <vector>
#include <string>
#include <algorithm>
#include <numeric>
#include <cctype>

int failures = 0;
#define CHECK(expr)                                                         \
    do {                                                                    \
        if (!(expr)) {                                                      \
            ++failures;                                                     \
            std::println("FAIL 第{}行: {}", __LINE__, #expr);              \
        }                                                                   \
    } while (0)

struct Student {
    std::string name;
    int score;
};

int main() {
    // 14.2 查询类
    std::vector<int> v{5, 3, 1, 4, 2, 4};
    CHECK(*std::max_element(v.begin(), v.end()) == 5);
    CHECK(*std::min_element(v.begin(), v.end()) == 1);
    CHECK(std::count(v.begin(), v.end(), 4) == 2);
    CHECK(std::count_if(v.begin(), v.end(), [](int x) { return x % 2 == 0; }) == 3);
    CHECK(std::all_of(v.begin(), v.end(), [](int x) { return x > 0; }));
    CHECK(std::any_of(v.begin(), v.end(), [](int x) { return x == 5; }));
    CHECK(std::none_of(v.begin(), v.end(), [](int x) { return x > 100; }));
    auto it = std::find_if(v.begin(), v.end(), [](int x) { return x > 4; });
    CHECK(it != v.end() && *it == 5);
    CHECK(std::find(v.begin(), v.end(), 99) == v.end());

    // 排序后二分查找
    std::vector<int> sorted = v;
    std::sort(sorted.begin(), sorted.end());
    CHECK(std::binary_search(sorted.begin(), sorted.end(), 4));

    // 14.3 修改类
    std::vector<int> rev{1, 2, 3, 4, 5};
    std::reverse(rev.begin(), rev.end());
    CHECK(rev[0] == 5);
    std::fill(rev.begin(), rev.end(), 0);
    CHECK(std::all_of(rev.begin(), rev.end(), [](int x) { return x == 0; }));
    std::replace(rev.begin(), rev.end(), 0, 7);
    CHECK(std::all_of(rev.begin(), rev.end(), [](int x) { return x == 7; }));

    // 组合拳：去重
    std::vector<int> dup{3, 1, 3, 2, 1, 3, 4};
    std::sort(dup.begin(), dup.end());
    dup.erase(std::unique(dup.begin(), dup.end()), dup.end());
    CHECK((dup == std::vector<int>{1, 2, 3, 4}));

    // 组合拳：删除所有偶数
    std::vector<int> del{1, 2, 3, 4, 5, 6};
    del.erase(std::remove_if(del.begin(), del.end(),
                             [](int x) { return x % 2 == 0; }),
              del.end());
    CHECK((del == std::vector<int>{1, 3, 5}));

    // 14.4 变换与生成
    std::vector<int> src{1, 2, 3};
    std::vector<int> dst(3);
    std::transform(src.begin(), src.end(), dst.begin(),
                   [](int x) { return x * x; });
    CHECK((dst == std::vector<int>{1, 4, 9}));
    CHECK(std::accumulate(src.begin(), src.end(), 0) == 6);
    CHECK(std::accumulate(src.begin(), src.end(), 1,
                          [](int a, int b) { return a * b; }) == 6);
    std::vector<int> seq(5);
    std::iota(seq.begin(), seq.end(), 0);
    CHECK((seq == std::vector<int>{0, 1, 2, 3, 4}));

    // 14.5 自定义类型排序
    std::vector<Student> stu{{"张三", 70}, {"李四", 95}, {"王五", 60}};
    std::sort(stu.begin(), stu.end(),
              [](const Student& a, const Student& b) {
                  return a.score > b.score;
              });
    CHECK(stu[0].name == "李四");
    CHECK(stu[2].name == "王五");

    // 14.6 ranges 版
    std::vector<int> rv{4, 2, 5, 1, 3};
    std::ranges::sort(rv);
    CHECK(std::ranges::is_sorted(rv));
    std::ranges::sort(rv, std::greater<>{});
    CHECK(rv[0] == 5);
    // 投影：按 Student.score 排序（升序）
    std::ranges::sort(stu, {}, &Student::score);
    CHECK(stu[0].name == "王五");
    CHECK(std::ranges::max_element(stu, {}, &Student::score)->name == "李四");

    // 14.7 汇总
    std::vector<int> vals{1, 2, 3, 4, 5};
    int even_count = std::ranges::count_if(vals, [](int x) { return x % 2 == 0; });
    CHECK(even_count == 2);
    CHECK(std::ranges::all_of(vals, [](int x) { return x >= 1; }));

    // 14.8 大小写转换
    std::string text = "Hello";
    std::transform(text.begin(), text.end(), text.begin(),
                   [](unsigned char c) { return std::toupper(c); });
    CHECK(text == "HELLO");

    if (failures == 0) std::println("全部通过");
    return failures;
}