fread

问题 My professor specified that file_1.txt be read 100 bytes at a time into a char array . I produced the following snippet code : int key; key = atoi(argv[1]); FILE *file_pointer; file_pointer = fopen(argv[2], "rb"); char buffer[100]; char output[sizeof(int)][100]; int output_counter = 0; int read_counter; int read_elements; while(read_elements = fread(buffer, 1, 100, file_pointer) > 0) { read_counter = 0; while(read_counter < 100) { printf("xor'ing %d and %d\n", key, buffer[read_counter]);

问题 This question already has answers here : Reading and writing binary file (7 answers) Closed 5 years ago . I want to write a ftp class with sockets, textfiles work pretty well to upload so far, but then I wanted to upload a bigger file, a movie, and it didn't work. The first 4096B are read well, but then it reads just nothing more. Maybe i'am using the wrong functions, please help my with my code. Here's my read function: bool CStream::Read (string * _OutString, unsigned int _iStartPos,

问题 fread : Specifying colClasses of file with 2 columns with same name, using col and col.1 does not work fread(file, colClasses(col = "character", col.1 = "character"), check.names = TRUE) It seems the check.names = TRUE is performed later, after the file is read. Is there any workaround to help do it. I need to preserve the precision of the columns col... 来源： https://stackoverflow.com/questions/58178779/fread-specifying-colclasses-of-file-with-2-columns-with-same-name-using-col-a

问题 So I need to write a function that reads all the elements inside a bit file. The point is that I don't know how many elements there could be inside, but I know what type of elements are. So I tried to write this function: void loadData(Parallelogram **array) { FILE *data; long size; //int numberOfElements = 0; int numberOfObjects = 0; if ((data = fopen(name, "rb"))!=NULL) { fseek(data, 0, SEEK_END); size = ftell(data); fseek(data, 0, SEEK_SET); if (size<(long)sizeof(Parallelogram)) { printf(

问题 I'm reading from file to string with fread function and then printing the string. I defined the string as array of chars with LONGNUM size(pre defined value). I'm reading 1 element 1 byte size each time. when printing the string with : printf("the string that read is: %s\n",buffer); the output is : the string that read is b I don't get it, why in the end of the stringi get this values? when printing the string with : printf("the string that read is : %c\n",buffer[0]); I get the write output

问题 I've been stuck on this for a few days and it's getting really frustrating. I'm using popen() to call a command line process and get its output and store it in a C string. I was using fgets() but it seems that breaks after a new line, so I'm using fread() . The only problem is that the returned C string is sometimes messed up. Here's my code: const char *cmd = "date";//This the shell command char buf[BUFSIZ];//Output of the command FILE *ptr; int c; if ((ptr = popen(cmd, "r")) != NULL) while

问题 I am reading a large .txt file (>1GB) into R via fread . I am reading the file in directly from a .zip archive, via a bash command: base = fread('unzip -p Folder.zip File.txt', sep = '|', header = FALSE, stringsAsFactors = FALSE, na.strings="", quote = "", col.names = col_namesMain) The text file separates entries via | so that a typical line might look like: RRX|||02020||333293||||12123 However, there are many places where empty entries are denoted by separators with no space between them, e

问题 Update As this.lau_ commented, it seems the problem is that no code is running at all on the server when the first file is running. I guess some configuration only allows one script to be run at once - or only one script per "user". Now I will investigate what can be causing that behaviour on the server. Thank you everyone for your help! . Original question I've got two PHP scripts, on separate files: /* The first file contains */ for($i = 0; $i < 10000; $i++){ $w = fopen($progress_file, "w")

问题 I have a file and there are many csv data in it. I want to read them and create new columns at one time and then combine to one datatable. I explain more here. Look at this pic: I want to create 2 new columns YEAR and MONTH based on the csv data title. ex. Take 201508 Sales Report(London) as an example. I want to create YEAR = 2015 and MONTH = 8 . I don't know how to do but I can read them at one time without create new columns. my_read_data <- function(path){ data <- data.table::fread(path,

问题 For our assignment we are given a copy of a wtmp log, and are expected to parse it, and output it in a sorted format, similar to the output of last . Now, I know that the file wtmp consists of a list of utmp structures. The file provided is guaranteed to contain at least one utmp structure and I'm supposed to assume all structures in the binary file are constructed correctly. I've read through man utmp , and I have successfully written a program to read in the structs from the binary file