版权声明:学无止境,好好学习 https://blog.csdn.net/m0_38116269/article/details/88566035
参考:
https://blog.csdn.net/c20081052/article/details/80603273
https://blog.csdn.net/jiongnima/article/details/55053059
发现了个很好的C++语法查询网站讲解清晰,而且可以在线运行例子。
#ifndef expr 查看expr定义了没有,如果没有定义会怎样怎样
#define ABCD 2
#include <iostream>
int main()
{
#ifdef ABCD
std::cout << "1: yes\n";
#else
std::cout << "1: no\n";
#endif
#ifndef ABCD
std::cout << "2: no1\n";
#elif ABCD == 2
std::cout << "2: yes\n";
#else
std::cout << "2: no2\n";
#endif
#if !defined(DCBA) && (ABCD < 2*4-3)
std::cout << "3: yes\n";
#endif
}
//Output:
1: yes
2: yes
3: yes
好了,今天开始阅读caffe.cpp了。