array-initialization

问题 This question already has answers here : String literals: Where do they go? (8 answers) Closed 7 days ago . int main() { char a[] = "123454321"; } "123454321" is a string literal and a string literal sets aside memory storage. a is defined by the statement which also causes memory storage. That is, this simple statement char a[] = "123454321"; causes two memory storage, one is for a and the other is for "123454321" . Is it right? 回答1: Yes, that's right. Note that the object on the right of

问题 Take the following example: private int[] list; public Listing() { // Why can't I do this? list = {4, 5, 6, 7, 8}; // I have to do this: int[] contents = {4, 5, 6, 7, 8}; list = contents; } Why can't I use shorthand initialization? The only way I can think of getting around this is making another array and setting list to that array. 回答1: When you define the array on the definition line, it assumes it know what the type will be so the new int[] is redundant. However when you use assignment it

问题 I have the following: typedef struct { uint8_t BlockID; uint32_t Copies; uint16_t Size; }NVMM_ConfigType; const NVMM_ConfigType NvmmCnf_Layout[6] = { { 1, 1, 4}, { 2, 3, 4}, { 5, 5, 16}, { 10, 1, 4}, { 11, 2, 32}, { 13, 1, 100}, }; Which seems fine to me, but, MISRA-C is giving the following error: MISRA C:2012 rule 10.3 violation: [R] The value of an expression shall not be assigned to an object with a narrower essential type or of a different essential type category I've tried to figure out

问题 I'd like to use an array initializer to build one byte array out of another byte array as well as some other bytes that form a header/trailer. Basically, I'd like to do something like this: byte[] DecorateByteArray(byte[] payload) { return new byte[] { 0, 1, 2, payload.GetBytes(), 3, 4, 5}; } GetBytes() above is fictional, unfortunately. Is there any nice/elegant way to do this? I solved this by using a BinaryWriter to write everything to a MemoryStream , and then converting this into a byte

问题 I have this code: let timer = new System.Diagnostics.Stopwatch() timer.Start() Array.zeroCreate<int> 100000000 timer.Stop() printfn "%ims" timer.ElapsedMilliseconds timer.Reset() timer.Start() Array.create 100000000 0 timer.Stop() printfn "%ims" timer.ElapsedMilliseconds I tested it and had these results: 0ms 200ms How does Array.zeroCreate create array so fast and it's guaranteed that all it's elements have default value? In other languages I know there are no such possibilities (as far as I

问题 By accident I found that the line char s[] = {"Hello World"}; is properly compiled and seems to be treated the same as char s[] = "Hello World"; . Isn't the first ( {"Hello World"} ) an array containing one element that is an array of char, so the declaration for s should read char *s[] ? In fact if I change it to char *s[] = {"Hello World"}; the compiler accepts it as well, as expected. Searching for an answer, the only place I found which mentioned this is this one but there is no citing of

问题 Hello I am a beginner in C programming language , recently i started learning arrays , I have studied that by default all values in an int array are garbage . Then why i am getting different values in these two cases. Case-1 int arr[5]; in this case from arr[0] till arr[4] we will have garbage values, but in next case. Case-2 int arr[5] = {1}; in this case arr[0] will have a value 1 and remaining from arr[1] to arr[4] will have value 0. My question is that, When in case-1 each un-initilized

问题 This question already has answers here : C compile error: “Variable-sized object may not be initialized” (7 answers) C error “variable-sized object may not be initialized” [duplicate] (3 answers) gcc complains: variable-sized object may not be initialized (3 answers) Closed last year . On initializing a Variable length array compiler gives an error message: [Error] variable-sized object may not be initialized Code snippet: int n; printf("Enter size of magic square: "); scanf("%d",&n); int

问题 This following code does not compile: int main() { int a[][] = { { 0, 1 }, { 2, 3 } }; } The error message produced is error: declaration of 'a' as multidimensional array must have bounds for all dimensions except the first int a[][] = { { 0, 1 }, ^ Is this specified by the standard? If so, why is that? I think deducing bounds here would be very easy. 回答1: Is this specified by the standard? Well, yeah. §8.3.4/3 When several “array of” specifications are adjacent, a multidimensional array type

问题 C99 provides a feature to initialize arrays by using both element-by-element & designated method together as: int a[] = {2,1,[3] = 5,[5] = 9,6,[8] = 4}; On running the code: #include <stdio.h> int main() { int a[] = {2,1,[3] = 5,[0] = 9,4,[6] = 25}; for(int i = 0; i < sizeof(a)/sizeof(a[0]); i++) printf("%d ",a[i]); return 0; } ( Note that Element 0 is initialized to 2 and then again initialised by designator [0] to 9 ) I was expecting that element 0 (which is 2 ) will be replaced by 9 (as