std::cout 条件打印

可以使用条件运算符 ?: 来进行条件打印，例如：

int x = 10;
int y = 20;
std::cout << ((x > y) ? "x is greater than y" : "x is less than or equal to y") << std::endl;

输出结果为 "x is less than or equal to y"。