cb25a_c++_函数对象简介
预定义的函数对象
https://blog.csdn.net/txwtech/article/details/104382505
negate()
plus()
minus()
multilies()
divides()
modulus()
equal_to()
not_equal_to()
less()
greater()
less_equal()
greater_equal()
logical_not()
logical_and()
logical_or()
