variable-length

问题 in variable-length parameters function, the '...' must be place last. And default value enabled parameters must be last, too. so, how about both needed in the same one function? Now I have a log utility: void MyPrint(int32_t logLevel, const char *format, ...), which used to print log according to 'logLevel'. However, sometimes I hope it can be used as: MyPrint("Log test number%d", number), without 'logLevel' needed. The question: Default arguments and variadic functions didn't help. 回答1: In

问题 I have a bit weird requirement where I need to generate Random numbers of the length that is given by user. User can give Minimum Length and the Maximum Length and I need to generate the random numbers which consist of the character length between this range. For example if the Minimum Length is 6 and Maximum Length is 10 then I need to generate the random numbers whose number of characters has to be between the range 6 and 10 . For this example following can be the random generators: 123456,

来源： https://stackoverflow.com/questions/23970451/how-do-i-expand-a-long-number-ending-in-e-to-show-in-expanded-form

问题 The following line of code, which creates a variable-length array on the stack: char name[length] = {'\0'}; Generates the following compiler diagnostics: error: variable-sized object may not be initialized warning: excess elements in array initializer warning: (near initialization for ‘name’) What options are available to me for initializing VLAs? Am I forced to use a line such as: memset(name, 0, sizeof(name)); Instead? 回答1: Yes, you must write code for the initialisation of VLAs (which

问题 I could not FTP a variable length file to mainframe; the operation was success, but the dataset generated on mainframe is not correct; can anyone help me. procedures. I have created a variable length dataset on mainframe. DSN=.TEST.DATA1 LRECL=16 Its content have 5 records, each has 12 characters: 000001 11AAAA000001 000002 11AAAA000002 000003 11AAAA000003 000004 11AAAA000004 000005 11AAAA000005 download the dataset to linux using FTP client on a linux platform ftp -v -n< user prompt binary

问题 I'm trying to build PTPv2 protocol using Scapy. There are few message types in this protocol, so I use ConditionalField to describe the different fields options: class PTPv2(Packet): name = "Precision Time Protocol V2" fields_desc = [ # Header BitField('transportSpecific', 1, 4), BitEnumField('messageType', 0, 4, Message_Types), ByteField('versionPTP', 2), LenField('messageLength', None), ByteField('subdomainNumber', 0), ByteField('empty1', 0), XShortField('flags', 0), LongField('correction',

问题 I want to do some exercise about va_list. This is my code. int myscanf( char* fmt, ... ) { va_list ap; va_start ( ap, fmt ); vfscanf ( stdin, fmt, ap ); va_end ( ap ); } int main() { int a, b; myscanf( "%d %d", &a, &b ); } As I shown above, I have written a scanf() and it is work. Now I want to redirect the value of arguments in myscanf(). For example, I can redirect fmt to the space which is allocated in myscanf() int myscanf( char* fmt, ... ) { char newFmt[10] = "%d %d"; va_list ap; va

问题 This question already has answers here : Numpy array dimensions (7 answers) Closed 2 years ago . If I use len(np.array([[2,3,1,0], [2,3,1,0], [3,2,1,1]])) , I get back 3. Why is there no argument for len() about which axis I want the length of in multidimensional arrays? This is alarming. Is there an alternative? 回答1: What is the len of the equivalent nested list? len([[2,3,1,0], [2,3,1,0], [3,2,1,1]]) With the more general concept of shape , numpy developers choose to implement __len__ as

问题 Before variable-length arrays were supported, I would dynamically allocate them like this: int foo(size_t n) { int *arr = malloc(n * sizeof int); if (!arr) return ENOMEM; /* not enough memory */ . . else do stuff with arr[] . free(arr); return 0; } With variable-length arrays I can now make it look cleaner: int bar(size_t n) { int arr[n]; . . do stuff with arr[] . return 0; } But now I have no "out of memory" checking. In fact, the program crashes if n is too big. How can I gracefully bail

问题 Before variable-length arrays were supported, I would dynamically allocate them like this: int foo(size_t n) { int *arr = malloc(n * sizeof int); if (!arr) return ENOMEM; /* not enough memory */ . . else do stuff with arr[] . free(arr); return 0; } With variable-length arrays I can now make it look cleaner: int bar(size_t n) { int arr[n]; . . do stuff with arr[] . return 0; } But now I have no "out of memory" checking. In fact, the program crashes if n is too big. How can I gracefully bail