什么是<？=在C ++？ [英] What is <?= in C++?

问题描述

可能重复：

C extension：<？和>？运算符

查看顶部答案的此 Google代码Jam 。它是C ++代码，它必须已经编译，它包含如下的语句：

Take a look at the top answer (by sclo) to problem D of this Google Code Jam. It's C++ code, it must have compiled, and it contains statements such as this one:

double& ret = F[mask][cur][b];
if(j==cur) {
  ret<?=f(tmp,j,b||bad[i])+M[cur][i];   // WTF is <?=   ???
}

这不会在Visual Studio 2008中编译。<？= 是什么意思？

This doesn't compile in my Visual Studio 2008. What does the <?= mean?

推荐答案

这是一个gcc扩展： C扩展名：< ;?和>？运算符

It's a gcc extension: C extension: <? and >? operators

最近的手册说：

G ++最小和最大运算符（'<？'和'>？'） ><？= '）和'>？= '）已被弃用，现在从G ++中删除。应该修改使用这些运算符的代码以使用 std :: min 和 std :: max p>

The G++ minimum and maximum operators (‘<?’ and ‘>?’) and their compound forms (‘<?=’) and ‘>?=’) have been deprecated and are now removed from G++. Code using these operators should be modified to use std::min and std::max instead...

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