C++中+=和=+的区别
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Difference between += and =+ in C++
提问by spurra
While programming in C++, I often confuse both "+=" and "=+", the former being the operator I actually mean. Visual Studio seems to accept both, yet they behave differently and is a source for a lot of my bugs. I know that a += b is semantically equivalent to a = a+b, but what does "=+" do?
在用 C++ 编程时，我经常混淆“+=”和“=+”，前者是我真正指的运算符。Visual Studio 似乎接受两者，但它们的行为不同，并且是我的许多错误的来源。我知道 a += b 在语义上等同于 a = a+b，但是“=+”有什么作用呢？
回答by Daniel A. White
=+is really = +(assignment and the unary +operators).
=+是真的= +（赋值和一元运算+符）。
In order to help you remember +=, remember that it does addition first, then assignment. Of course that depends on the actual implementation, but it should be for the primitives.
为了帮助你记住+=，记住它是先加法，后赋值。当然，这取决于实际的实现，但它应该用于原语。
回答by Ivan Ishchenko
a =+ bmeans a = +bmeans a = b
a =+ b手段a = +b手段a = b
回答by Abdelrahman
if you see =the first , it means you re-declare your variable value ,
but if you face +the first it means that you order the compiler to increment the value of the variable , keep it in you mind
如果您看到=第一个，则意味着您重新声明了变量值，但是如果您遇到+第一个，则意味着您命令编译器增加变量的值，请记住它
int x=20 ;
x=+10 ;
cout<< x <<endl ; // x = 10
x+=10 ;
cout<< x<<endl ; // x= 10+10 = 20
