global-variables

问题 I'm a little Confused about this code result: #include <stdio.h> int g; void afunc(int x) { g = x; /* this sets the global to whatever x is */ } int main(void) { int g = 10; /* Local g is now 10 */ afunc(20); /* but this function will set it to 20 */ printf("%d\n", g); /* so this will print "20" */ return 0; } Why the result is 10 Not 20 ? 回答1: Calling afunc changes the global g , and main retains its local g . Entering a function doesn’t swap its scope with the global scope. Each function*

问题 def pLatin_converter (self): movetoend = "" index = 0 global pig = "" I'm getting an 'invalid syntax' on the global pig = "" line and I don't understand why. 回答1: The global variable can't be assigned a value in the global statement. Split the two: global pig pig="" 来源： https://stackoverflow.com/questions/49279682/why-do-i-get-an-invalid-syntax-when-defining-a-global-variable

问题 So I have reduced the problem to a very simple program of an empty main() function and a very simple class as follows. A.cpp #include <iostream> class A { public: A() {std::cout<<"Inside A()"<<std::endl;} }; static A a; test.cpp #include "A.cpp" int main() {} Now consider 2 options for building this simple program into 2 different executables: Generating program #1: Compile with the following command (generate .o files from the .cpp files): g++ -c test.cpp A.cpp And then link with the

问题 I’m working on a stateful and websocket server on Node. We require a piece of read-only data that is important for the biz logic and save it in Node’s global scope, and recently we have to invalidate this require cache and re-require to allow changes of this piece of data at runtime. My question is should we worry simply reassigning the global variable the result of the re-require would cause issues between concurrent connections which read this single copy of data at different phases? Thanks

问题 I am trying to delete a node from a linked list but I am still new to the concept of double pointers so I tried using a global variable to hold the head pointer instead. However, I get the wrong results when I try to print my list after deleting the middle node. I saw this question deleting a node in the middle of a linked list and I don't know how is my delete node function different from the answer. Here is my code: #include <stdio.h> #include <stdlib.h> typedef unsigned char u8; typedef

问题 This question already has answers here : After forking, are global variables shared? (4 answers) Closed 4 years ago . Lately I've encountered an interesting situation: I've defined a global static variable in a dynamically linked library (.so). This library always being called under fork(). What I've noticed is that the global variable always being called with init values, and doesn't change them between the calls. I have a few questions about that: Why does being 'forked' change the basic

问题 I have the following functions in Python3.7 def output_report(): sheet_dict = {1: 'All', 2: 'Wind', 3: 'Soalr'} sheet_name = sheet_dict[sheet_num] file_name = f'{file_name}_{sheet_name}_row_{row_num}.csv' if row_num else f'{file_name}_{sheet_name}.csv' return file_name def test_file(x): file_name = output_report(sheet_num) return f'{x}_{file_name}' def good_func(): sheet_num = 2 row_num = 2 a = test_file('new file') return a when I call: good_func() It raises an error that: NameError: name

问题 In Xamarin, I am wanting to store data and global variables using the Application object. I looked at this resource for this code: http://www.helloandroid.com/tutorials/maintaining-global-application-state Here is my code: public class HelloApplication : Application { private int GlobalVariable = 1; public int GetGlobalVariable() { return GlobalVariable; } public void SetGlobalVariable(int GlobalVariable) { this.GlobalVariable = GlobalVariable; } } I am trying to reference the class using

问题 In Xamarin, I am wanting to store data and global variables using the Application object. I looked at this resource for this code: http://www.helloandroid.com/tutorials/maintaining-global-application-state Here is my code: public class HelloApplication : Application { private int GlobalVariable = 1; public int GetGlobalVariable() { return GlobalVariable; } public void SetGlobalVariable(int GlobalVariable) { this.GlobalVariable = GlobalVariable; } } I am trying to reference the class using

问题 In many of the answers that I found here were said the following words: Global variables in a single translation unit (source file) are initialized in the order in which they are defined. or Within the same compilation unit the order is well defined: The same order as definition. etc. But where can I see these words in the standard of C++? I would like to get a one or few concrete paragraph's where such behavior is described. I can not find it myself, and I do not know who to ask. 回答1: 6.6.3