如: string s = "2021_09-15 14:25:37.045";
char* c = s.c_str();
这时会报错:invalid conversion from `const char*' to `char*'
解决方法: char* c = const_cast<char *>(s.c_str());
如: string s = "2021_09-15 14:25:37.045";
char* c = s.c_str();
这时会报错:invalid conversion from `const char*' to `char*'
解决方法: char* c = const_cast<char *>(s.c_str());