如何将 std::string 复制到无符号字符数组？

Question

如何将 std::string（样本）复制到无符号字符数组（陷阱）？

int main() {
    unsigned char trap[256];
    std::string sample = ".1.3.6.1.4";
    strcpy(trap,sample.c_str());
    std::cout << trap << std::endl;
}

上面的代码抛出错误：

time.cpp: In function ‘int main()’:
time.cpp:20: error: invalid conversion from ‘unsigned char*’ to ‘char*’
time.cpp:20: error:   initializing argument 1 of ‘char* strcpy(char*, const char*)’

Answer 1

这是一种方法：

#include <algorithm>
#include <iostream>

auto main() -> int
{
    unsigned char trap[256];
    std::string sample = ".1.3.6.1.4";
    std::copy( sample.begin(), sample.end(), trap );
    trap[sample.length()] = 0;
    std::cout << trap << std::endl;
}

另外检查缓冲区是否足够大可能是个好主意。

Answer 2

也可以使用 reinterpret_cast：

int main() {
    std::string sample = ".1.3.6.1.4";
    auto uCharArr = reinterpret_cast<unsigned char*>(sample.c_str());
}