C++ 字符串大小写转换：将所有小写字母转换为大写字母

#include \n#include \n#include \n\nint main() {\n std::string str; \n std::getline(std::cin, str); \n \n for (char& c : str) { \n if (std::islower(c)) { \n c = std::toupper(c); \n } \n } \n \n std::cout << str << std::endl; \n \n return 0; \n}