lvalue required as left operand of assignment

关于左值的问题
这样是有问题的d>0?(c+=1):(d?a+=1:b+=1);
这样是没问题的if(d>0)
c+=1;
else if(d)
a+=1;
else
b+=1;
不理解为什么，请大神给好好讲一讲有关左值的问题

d>0?(c+=1):(d?a+=1:**_（_**b+=1**_）_**);

我试了没问题的啊

应该没有问题啊。你用的什么编译器？

d>0?(c+=1):(d?a+=1:b+=1);
如果d > 0;的话， 冒号后面的表达式即(d ? a +=1 : b+=1)不用计算了。

你的意思指的是这个吗？

是不是 ？：表达式里：左右的表达式的地位是不一样的？左边允许是左值，右边不允许？
不清楚为什么，同问。

http://stackoverflow.com/questions/6966299/error-lvalue-required-in-this-simple-c-code-ternary-with-assignment
优先级的问题。

For example, in C, the syntax for a conditional expression is:

logical-OR-expression ? expression : conditional-expression
while in C++ it is:

logical-OR-expression ? expression : assignment-expression
Hence, the expression:

e = a < d ? a++ : a = d
is parsed differently in the two languages. In C, this expression is a syntax error, but many compilers parse it as:

e = ((a < d ? a++ : a) = d)
which is a semantic error, since th

e result of the conditional-expression (which might be a++) is not an lvalue. In C++, it is parsed as:

e = (a < d ? a++ : (a = d))
which is a valid expression.