怎样用C++制作单词统计工具 字符串处理与map容器应用

std::map

std::map<std::string, int>

std::string

int

#include <iostream>
#include <fstream>
#include <string>
#include <map>
#include <algorithm> // for std::transform
#include <cctype>    // for ::tolower, ::ispunct
#include <sstream>   // for std::stringstream

// 辅助函数：清洗单词，转小写并去除标点
std::string cleanWord(const std::string& word) {
    std::string cleaned = word;
    // 将所有字符转为小写
    std::transform(cleaned.begin(), cleaned.end(), cleaned.begin(),
                   [](unsigned char c){ return std::tolower(c); });

    // 移除标点符号
    cleaned.erase(std::remove_if(cleaned.begin(), cleaned.end(),
                                 [](unsigned char c){ return std::ispunct(c); }),
                  cleaned.end());
    return cleaned;
}

int main() {
    std::ifstream inputFile("input.txt"); // 假设输入文件名为 input.txt
    if (!inputFile.is_open()) {
        std::cerr << "无法打开文件！" << std::endl;
        return 1;
    }

    std::map<std::string, int> wordCounts;
    std::string line;

    while (std::getline(inputFile, line)) { // 逐行读取
        std::stringstream ss(line);
        std::string word;
        while (ss >> word) { // 从行中逐个提取单词
            std::string cleaned = cleanWord(word);
            if (!cleaned.empty()) { // 确保清洗后不是空字符串
                wordCounts[cleaned]++;
            }
        }
    }

    // 输出结果
    for (const auto& pair : wordCounts) {
        std::cout << pair.first << ": " << pair.second << std::endl;
    }

    inputFile.close();
    return 0;
}

stringstream

map

std::ifstream

>>

std::getline(inputFile, line)

std::stringstream

stringstream

>>

std::transform

std::tolower

>>

std::remove_if

std::ispunct

std::remove_if

erase

std::map

map

map

map

wordCounts[cleanedWord]

cleanedWord

map

int

++

std::unordered_map

std::map

map

unordered_map

iostream

stdio

main

std::ios_base::sync_with_stdio(false);

std::cin.tie(NULL);

std::map

std::unordered_map

std::ifstream::is_open()

./word_counter my_document.txt

map

std::vector<std::pair<std::string, int>>

std::sort

[](const auto& a, const auto& b){ return a.second > b.second; }