dynamic-arrays

问题 I'm not a good English speaker. so in my program I want to copy a text who exists in a txt file to an array. typedef struct Chaine { char * Lachaine; int Taille_C; } Chaine ; int main (void) { Chaine *Tab_Texte=NULL; Tab_Texte=(Chaine*)malloc(sizeof(Chaine)); FILE* Texte= NULL; Texte = fopen("chaines", "r"); fseek(Texte, 0, SEEK_END); Tab_Texte->Taille_C=ftell(Texte); fseek(Texte, 0, SEEK_SET); Tab_Texte->Lachaine=NULL; Tab_Texte->Lachaine=(char*)malloc(sizeof(char)*Tab_Texte->Taille_C);

问题 I need to create a program which calculates the cumulative sum of a dynamically allocated vector and the vector should be filled with random values (not values from stdin) ​​using only pointers . I couldn't think of a version that uses only pointers (i'm kinda new to this matter). This is the code I have so far: #include <stdio.h> #include <malloc.h> int main() { int i, n, sum = 0; int *a; printf("Define size of your array A \n"); scanf("%d", &n); a = (int *)malloc(n * sizeof(int)); printf(

问题 I was getting realloc(): invalid next size for a program. So I just coded this to understand what's happening. #include <stdio.h> #include <stdlib.h> int main() { char *inp; printf("%lu ",sizeof(inp)); char *res = (char*)malloc(15*sizeof(char*)); printf("%lu ",sizeof(res)); res = "hello world"; printf("%lu\n",sizeof(res)); return 0; } And surprisingly it outputs 8 8 8 . Can anyone explain why is it like that? Why is it 8 by default? And how malloc() effects size of inp ? 回答1: You are using

问题 In Fortran 2003, the allocatable array is not interoperable with C. I suppose this has something to do with additional array information stored in memory which might disturb the C interpretation. But what if I declare a dummy argument as 1D assumed shape array? for example subroutine outter_subroutine(ma, size_ma) integer :: size_ma integer :: ma(size_ma) call fortran_subroutine(ma) end subroutine !----------------------------- subroutine fortran_subroutine(a) integer, intent(in) :: a(:)

问题 The following function below will add "1" to every column across the excel sheet. If I put =vbe(12) in A1, it will put "1" in columns "A1:L1". How can I translate this VBA to JavaScript for Google Sheets? Function vbe(Num As Long) As Variant Dim ary As Variant Dim i As Long ReDim ary(Num - 1) For i = 0 To Num - 1 ary(i) = 1 Next i vbe = ary End Function 回答1: You can write a custom formula that creates an array of "1"s with the length as a specified parameter, e.g. function myFunction

问题 Just to elaborate on the question asked. Given that you have a sequence from 0 to n (0,1,2, ... n-1,n). I want to return an array that contains all the possible permutations that fulfill the condition that adjacent numbers must have a difference greater than 1. For example, given the sequence (0,1,2,3), the only valid permutations would be (1,3,0,2) and (2,0,3,1). I actually already have a working function. function validSequences(n) { let all = [], baseSequence = [], startingValue = 0,

问题 I would like to use the new dynamic array functions in Excel (like FILTER , UNIQUE , SORT ) as a source for list validations. In the following example, all values in column A where the corresponding value in column B is at least 500 should appear. I use the following formula: =FILTER($A$2:$A$7;$B$2:$B$7>=500) Unfortunately, when I use the formula from cell D2 as a source, I get an error message: I have also tried to put the formula into a name and then reference the name as a source. But that

问题 Is it possible for the new function UNIQUE to be used across various columns & have the output spill into a single column? Desired output is UNIQUE values in one single column based on all of the values present in Columns: A, B, & C ( duplicates in red in example ) If I just use UNIQUE(A7:C7) I get a spill range across columns ( this doesn't even provide unique values across columns which was unexpected ) I also tried UNIQUE(A2:A6) & UNIQUE(B5:B10) & UNIQUE(C2:C5) but this just concatenated

问题 Is it possible for the new function UNIQUE to be used across various columns & have the output spill into a single column? Desired output is UNIQUE values in one single column based on all of the values present in Columns: A, B, & C ( duplicates in red in example ) If I just use UNIQUE(A7:C7) I get a spill range across columns ( this doesn't even provide unique values across columns which was unexpected ) I also tried UNIQUE(A2:A6) & UNIQUE(B5:B10) & UNIQUE(C2:C5) but this just concatenated

问题 In the C++20 standard, it is said that array types are implicit lifetime type . Does it mean that an array to a non implicit lifetime type can be implicitly created? The implicit creation of such an array would not cause creation of the array's elements? Consider this case: //implicit creation of an array of std::string //but not the std::string elements: void * ptr = operator new(sizeof (std::string) * 10); //use launder to get a "pointer to object" (which object?) std::string * sptr = std: