operator-precedence

applicative-order/call-by-value and normal-order/call-by-name differences

巧了我就是萌 提交于 2019-12-06 16:03:57
Background I am learning the sicp according to an online course and got confused by its lecture notes. In the lecture notes, the applicative order seems to equal cbv and normal order to cbn. Confusion But the wiki points out that, beside evaluation orders(left to right, right to left, or simultaneous), there is a difference between the applicative order and cbv: Unlike call-by-value, applicative order evaluation reduces terms within a function body as much as possible before the function is applied. I don't understand what does it mean by reduced. Aren't applicative order and cbv both going to

C++ Precedence definitive list [closed]

|▌冷眼眸甩不掉的悲伤 提交于 2019-12-06 13:53:58
Closed. This question is off-topic . It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 4 years ago . A quick search for C++ precedence yields many attempts. The disconcerting part is that they are all different. Most are assuredly wrong, albeit in minor details. I will include three. The first, from cppreference.com claims there are 16 levels of precedence. Learn.cpp has 18. A simpler table at university of Purdue is much simpler. http://en.cppreference.com/w/cpp/language/operator_precedence http://www.learncpp

Disambiguation of expressions with neighboring operators of different associativity and same precedence

和自甴很熟 提交于 2019-12-06 11:54:31
Say I have an expression as follows (where ⨁ and ⨂ are binary operators which have the same precedence level but not the same associativity): x ⨁ y ⨂ z Would y belong to ⨁ or ⨂ , and based on what criteria? According to the Edsgar Dijkstra's Shunting-yard algorithm if neighboring two operators in an expressions have the same precedence level then the expression is disambiguated based on the associativity of the second operator. If the second operator is left associative then the operand belongs to the first operator. If the second operator is right associative then the operand belongs to the

Chaining operation and order of evaluation on the same object

拈花ヽ惹草 提交于 2019-12-06 11:23:19
Consider a class MyClass with: a member function myClass& myFunction1(int) that modifies the object and returns *this a member function int myFunction2() const that does not modify the object Does the C++11/14 standard guarantee that: myclass.myFunction1(myclass.myFunction2()).myFunction1(myclass.myFunction2()); is equivalent to: myclass.myFunction1(myclass.myFunction2()); myclass.myFunction1(myclass.myFunction2()); No. The compiler can first call myclass.myFunction2() twice and then do the two myFunction1 calls in the first example code. But not in the second example code. There is nothing

Java - parentheses and assignment

拟墨画扇 提交于 2019-12-06 08:59:02
The code: int r=1; System.out.println(r + (r=2)); The output is: 3. But I expected 4 because I thought the code inside the parentheses is executed first? Official Docs on Operators says All binary operators except for the assignment operators are evaluated from left to right; assignment operators are evaluated right to left. So + is evaluated left-to-right ,where as assignment operators are evaluated right to left. Use this if you want 4 int r=1; System.out.println((r=2) + r); // execute + is left-to-right Associativity of + is left-to-right , and the value of the expression (r=2) is 2 . Refer

How do I parenthesize an expression?

半腔热情 提交于 2019-12-06 08:17:09
问题 I have an idea for a simple program to make that will help me with operator precedence in languages like C. The most difficult part of this is parenthesizing the expression. For example, I want this: *a.x++ = *b.x++ Converted to this: ((*(((a).(x))++)) = (*(((b).(x))++))) Which I did manually in these steps: *a.x++ = *b.x++ *(a).(x)++ = *(b).(x)++ *((a).(x))++ = *((b).(x))++ *(((a).(x))++) = *(((b).(x))++) (*(((a).(x))++)) = (*(((b).(x))++)) ((*(((a).(x))++)) = (*(((b).(x))++))) What is the

Parenthesis calculator for C/C++ expressions operator precedence

三世轮回 提交于 2019-12-06 07:44:06
After porting some obfuscated C code into C++ (namely Fairy-Max chess engine by Harm Geert Muller), I get lots of warnings similar to these: suggest parentheses around comparison in operand of '&' [-Werror=parentheses] suggest parentheses around '+' in operand of '&' While turning off the warnings is not an option, the solution is to add parenthesis in expressions according to the operator precedence . For example: if(z&S&&!ab&K==INF&d>2&v>V&v<Beta){ needs to be transformed into this: if((z&S) && ((!ab)&(K==INF)&(d>2)&(v>V)&(v<Beta))) { But doing this manually is quite time-consuming. I tried

Operator precedence or Maximal Munch Rule comes first for Unary Operators

我与影子孤独终老i 提交于 2019-12-06 05:16:45
问题 Here I am having the following piece of code: int a,b,x; a=b=1; x=a+++b; Now the value of x will be 2 as a is first being post incremented and then it is being added to b . Following is the compiled byte code : 0 iconst_1 1 dup 2 istore_2 [b] 3 istore_1 [a] 4 iload_1 [a] 5 iinc 1 1 [a] 8 iload_2 [b] 9 iadd 10 istore_3 [x] So the expression will be equivalent to x = (a++) + b . Now the other expression x=a++++b , won't compile because of the maximal munch rule . It will become x = (a++) ++ b

Precedence of Logical Operators in C [duplicate]

允我心安 提交于 2019-12-06 03:06:56
问题 This question already has answers here : Closed 8 years ago . Possible Duplicate: why “++x || ++y && ++z” calculate “++x” firstly ? however,Operator “&&” is higher than “||” If you look at C's precedence table, you'll see that && has higher precedence than ||. But take a look at the following code: a=b=c=1; ++a || ++b && ++c; printf("%d %d %d\n",a,b,c); It prints out "2 1 1", meaning that the "++a" is evaluated first, and once the program sees a TRUE there it stops right there, because what

gcc linker library search order; paths plus static vs shared

余生颓废 提交于 2019-12-06 00:11:56
问题 Reading through the gcc manual, I believe the following two statements are true: Library search paths specified on the command line are searched before "default" paths (which I assume means stuff in the LIBRARY_PATH environment variable) Shared libraries will be linked in preference to static libraries (in the absence of flags saying to do otherwise) But which of these two dominates? For example, if I type gcc myprog.cpp -o myprog -Lmypath -lmylibrary and in mypath there is the static library