如何在char - C++向量的向量中使用copy_if

#include <vector>
#include <algorithm>

std::vector<std::vector<char>> charVector = {{'a', 'b', 'c'}, {'d', 'e', 'f'}, {'g', 'h', 'i'}};

std::vector<char> targetVector;

std::copy_if(charVector.begin(), charVector.end(), std::back_inserter(targetVector), [](const std::vector<char>& innerVector) {
    return std::all_of(innerVector.begin(), innerVector.end(), [](char c) {
        return std::islower(c);
    });
});

for (const auto& ch : targetVector) {
    std::cout << ch << " ";
}

#include <iostream>
#include <vector>
#include <algorithm>

int main() {
    std::vector<std::vector<char>> charVector = {{'a', 'b', 'c'}, {'d', 'e', 'f'}, {'g', 'h', 'i'}};
    std::vector<char> targetVector;

    std::copy_if(charVector.begin(), charVector.end(), std::back_inserter(targetVector), [](const std::vector<char>& innerVector) {
        return std::all_of(innerVector.begin(), innerVector.end(), [](char c) {
            return std::islower(c);
        });
    });

    for (const auto& ch : targetVector) {
        std::cout << ch << " ";
    }

    return 0;
}