C++ 字符串后缀删除算法

#include <iostream>
#include <string>

int main() {
    std::string word;
    std::cin >> word;

    if (word.size() >= 2 && word.substr(word.size() - 2) == 'er') {
        word = word.substr(0, word.size() - 2);
    } else if (word.size() >= 2 && word.substr(word.size() - 2) == 'ly') {
        word = word.substr(0, word.size() - 2);
    } else if (word.size() >= 3 && word.substr(word.size() - 3) == 'ing') {
        word = word.substr(0, word.size() - 3);
    }

    std::cout << word << std::endl;

    return 0;
}