When I do this: count = ++count; Why do i get the warning - The assignment to variable count has no effect ? This means that count is incremented and then assigned to itself or something else ? Is it the same as just ++count ? What happens in count = count++; ? Why don't I get a warning for this ?
当我这样做时:count = ++计数;为什么我得到警告-变量计数的赋值没有影响?这意味着计数是递增的然后分配给它自己或者其他的东西?是否与++计数相同?在count = count++中发生了什么?吗?为什么不给我一个警告呢?
4 个解决方案
#1
13
count++ and ++count are both short for count=count+1. The assignment is built in, so there's no point to assigning it again. The difference between count++ (also knows as postfix) and ++count (also known as prefix) is that ++count will happen before the rest of the line, and count++ will happen after the rest of the line.
count++ ++ +count =count+1。作业是内置的，所以没有必要再分配。count++(也称为后缀)和++count(也称为前缀)的区别在于，在其余的行之前，++计数将发生，而count++会发生在其余的行之后。
If you were to take apart count=count++, you would end up with this:
如果你拆开count=count++，你就会得到这样的结果:
count = count;
count = count+1;
Now you can see why postfix won't give you a warning: something is actually being changed at the end.
现在您可以看到为什么postfix不会给您一个警告:实际上，在最后会发生一些变化。
If you take apart count=++count, you would end up with this:
如果你拆开count=++count，你就会得到这样的结果:
count = count+1;
count = count;
As you can see, the second line of code is useless, and that's why the compiler is warning you.
如您所见，第二行代码是无用的，这就是编译器警告您的原因。
#2
3
Breaking the statement up you are basically writing:
打破陈述句你基本上是在写:
++count;
count = count;
As you can see count=count does nothing, hence the warning.
您可以看到count=count不做任何事情，因此警告。
#3
3
the ++ operator is a shortcut for the following count = count + 1. If we break your line count = ++count it responds to count = count+1 = count
++运算符是下面count = count + 1的快捷方式。如果我们中断了您的行计数= ++计数，则计数= count+1 = count。
#4
3
To expand a little, count++ is postfix. It takes place after other operations so if you did something like
要扩展一点，count++是后缀。它发生在其他操作之后，如果你做了类似的事情。
int a = 0, b = 0;
a = b++;
a would be 0, b would be 1. However, ++count is prefix if you did
a是0 b是1。但是，如果你做了，那么++计数就是前缀。
int a = 0, b = 0;
a = ++b;
then a and b would both be 1. If you just do
然后a和b都是1。如果你只是做
count++;
or
或
++count;
then it doesn't matter, but if you are combining it with something else, it will
那没关系，但如果你把它和别的东西结合起来，它就会。
#1
13
count++ and ++count are both short for count=count+1. The assignment is built in, so there's no point to assigning it again. The difference between count++ (also knows as postfix) and ++count (also known as prefix) is that ++count will happen before the rest of the line, and count++ will happen after the rest of the line.
count++ ++ +count =count+1。作业是内置的，所以没有必要再分配。count++(也称为后缀)和++count(也称为前缀)的区别在于，在其余的行之前，++计数将发生，而count++会发生在其余的行之后。
If you were to take apart count=count++, you would end up with this:
如果你拆开count=count++，你就会得到这样的结果:
count = count;
count = count+1;
Now you can see why postfix won't give you a warning: something is actually being changed at the end.
现在您可以看到为什么postfix不会给您一个警告:实际上，在最后会发生一些变化。
If you take apart count=++count, you would end up with this:
如果你拆开count=++count，你就会得到这样的结果:
count = count+1;
count = count;
As you can see, the second line of code is useless, and that's why the compiler is warning you.
如您所见，第二行代码是无用的，这就是编译器警告您的原因。
#2
3
Breaking the statement up you are basically writing:
打破陈述句你基本上是在写:
++count;
count = count;
As you can see count=count does nothing, hence the warning.
您可以看到count=count不做任何事情，因此警告。
#3
3
the ++ operator is a shortcut for the following count = count + 1. If we break your line count = ++count it responds to count = count+1 = count
++运算符是下面count = count + 1的快捷方式。如果我们中断了您的行计数= ++计数，则计数= count+1 = count。
#4
3
To expand a little, count++ is postfix. It takes place after other operations so if you did something like
要扩展一点，count++是后缀。它发生在其他操作之后，如果你做了类似的事情。
int a = 0, b = 0;
a = b++;
a would be 0, b would be 1. However, ++count is prefix if you did
a是0 b是1。但是，如果你做了，那么++计数就是前缀。
int a = 0, b = 0;
a = ++b;
then a and b would both be 1. If you just do
然后a和b都是1。如果你只是做
count++;
or
或
++count;
then it doesn't matter, but if you are combining it with something else, it will
那没关系，但如果你把它和别的东西结合起来，它就会。