declaration

问题 As the question states, what exactly are the implications of having the 'implicit declaration of function' warning? We just cranked up the warning flags on gcc and found quite a few instances of these warnings and I'm curious what type of problems this may have caused prior to fixing them? Also, why is this a warning and not an error. How is gcc even able to successfully link this executable? As you can see in the example below, the executable functions as expected. Take the following two

问题 I'm not able to understand this statement of code that I came across during my interview. int(*(*ptr[3])(char*))[2]; I've tried looking at an IDE but all I have is that it is an array of data type int (*(*[3])(char *)) I wasn't able to understand this. 回答1: May be you could just break it down one at a time to understand the syntax better. First start up with a simple definition without the array notation int(*(*ptr)(char*)); So ptr is a function pointer that takes a char pointer as an

问题 From the C++11 standard, §7.3.3[namespace.udecl]/1: A using-declaration introduces a name into the declarative region in which the using-declaration appears. using-declaration : using typename opt nested-name-specifier unqualified-id ; using :: unqualified-id ; The member name specified in a using-declaration is declared in the declarative region in which the using-declaration appears. What do they mean by the name being declared in the declarative region where the using-declaration occurs?

问题 This question's purpose is to only gain knowledge or information for me and many like me. So my question is: Is it necessary to Initialize / Declare a variable before a loop or a function? Asking this question is for my confusion because whether I initialize / declare variable before or not my code still works. I'm sharing a demo code for what I actually mean: $cars = null; foreach ($build as $brand) { $cars .= $brand . ","; } echo $cars; OR foreach ($build as $brand) { $cars .= $brand . ",";

问题 This question's purpose is to only gain knowledge or information for me and many like me. So my question is: Is it necessary to Initialize / Declare a variable before a loop or a function? Asking this question is for my confusion because whether I initialize / declare variable before or not my code still works. I'm sharing a demo code for what I actually mean: $cars = null; foreach ($build as $brand) { $cars .= $brand . ","; } echo $cars; OR foreach ($build as $brand) { $cars .= $brand . ",";

问题 Hey I'm having trouble understanding on how structs get passed to functions as pointers because i want to modify my structs later in my project. So I'm creating a game that has rooms and this function creates a 2d array of the world. I'm passing in struct room and struct World because I'm storing each room in a cord in World struct which is a 2d array. When i got print out each room, it doesn't print anything out and i think the problem is with my pointers. So my first function that's in a

问题 In JavaScript, it is possible to declare multiple variables like this: var variable1 = "Hello, World!"; var variable2 = "Testing..."; var variable3 = 42; ...or like this: var variable1 = "Hello, World!", variable2 = "Testing...", variable3 = 42; Is one method better/faster than the other? 回答1: The first way is easier to maintain. Each declaration is a single statement on a single line, so you can easily add, remove, and reorder the declarations. With the second way, it is annoying to remove

问题 I have to build a nested structure to store some basic information about some person (name, age, address). So I created a structure called "info" and to hold the address I created another nested structure inside "info" called "address". But whenever I prompt to store the values using a for loop, I get errors. What is the problem here and how can I solve it? [Error] 'struct Info' has no member named 'address' [Warning] declaration does not declare anything [enabled by default] #include <stdio

问题 I'm working on porting some old K&R code to ANSI C, so I'm writing missing function prototype declarations. A lot of the function definitions have parameters with the register storage class, but I'm not sure if the register storage class specifier can be omitted in the function prototype? With and without the register storage class specific declaration, the code compiles correctly (I tried GCC, VC++ and Watcom C). I could not find any information in the ISO/ANSI C89 standard on what is the

问题 I want to separate my JavaScript function documentation into TypeScript .d.ts files. For example: components/ Button/ Button.jsx # JavaScript component Button.d.ts # TypeScript documentation with prop types Similarly how Material UI does this. https://github.com/mui-org/material-ui/tree/master/packages/material-ui/src/Button My issue is that TypeScript & VSCode does not recognize the .d.ts file for the current JavaScript file. In my setup, I have the following Button.d.ts file: interface