file-handling

问题 I try to create files and write the contents dynamically. Below is my code. $sites = realpath(dirname(__FILE__)).'/'; $newfile = $sites.$filnme_epub.".js"; if (file_exists($newfile)) { $fh = fopen($newfile, 'a'); fwrite($fh, 'd'); } else { echo "sfaf"; $fh = fopen($newfile, 'wb'); fwrite($fh, 'd'); } fclose($fh); chmod($newfile, 0777); // echo (is_writable($filnme_epub.".js")) ? 'writable' : 'not writable'; echo (is_readable($filnme_epub.".js")) ? 'readable' : 'not readable'; die; However, it

问题 int main() { FILE *ft; char ch; ft=fopen("abc.txt","r+"); if(ft==NULL) { printf("can not open target file\n"); exit(1); } while(1) { ch=fgetc(ft); if(ch==EOF) { printf("done"); break; } if(ch=='i') { fputc('a',ft); } } fclose(ft); return 0; } As one can see that I want to edit abc.txt in such a way that i is replaced by a in it. The program works fine but when I open abc.txt externally, it seemed to be unedited. Any possible reason for that? Why in this case the character after i is not

问题 FILE *fd; if (fd=fopen(fileName,"r") == NULL) { printf("File failed to open"); exit(1); } This is a code snippet. When I compile it with gcc, i get the following warning:- warning: assignment makes pointer from integer without a cast When I put fd=fopen(argv[2],"r") within brackets, the problem gets solved.. I am not able to understand where am i converting integer to pointer when the brackets are not put. 回答1: Due to operator precedence rules the condition is interpreted as fd=(fopen

问题 Let's say I have a C/C++ file named userfile.c . Using Python, how can I invoke the local gcc compiler so that the file is compiled and an executable is made? More specifically, I would like to provide some input (stdin) via some file input.txt and I want to save the standard output into another file called output.txt . I saw some documentation that I will need to use subprocess, but I'm not sure how to call that and how to provide custom input. 回答1: A simple solution will be as given below:

问题 I need to compile my code based on version number of the project i am working on. In short, i will read the version number from a file and enable or disable certain part of my code/. How can i read the version number from a file at compile time in c/c++?. I am trying to do something like this static const unsigned int version = #include "version" ; I am getting compiler error. 回答1: file.c #include <stdio.h> static const float version = #include "file.h" ; int main() { printf("Version is : %f

问题 One of the purposes of the library of which I am developing is to retrieve a specified amount of bytes from a file, in this specific case I am wishing for access to /dev/random to retrieve entropy based random sequences. My main issue with fread is that it will hang indefinitely when waiting for more entropy, and this is unwanted. My next choice would have been wrapping fread with feof to take bytes in chunks, then I could at least provide percentages complete for a better experience,

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 6 years ago . I have a timer set to invoke a class that contains pdf generating codes.I have set the file path where it needs to be saved..but it is showing exception as java.io.FileNotFoundException : D:\ (The system cannot find the path specified) .I dont know where is the mistake.. Here is my code.. try { OutputStream file

问题 i have a csv file and which look like this : 1;53453;45847865 1;37567;53687686 . . . . n. 1;999768;5645644 and i want to open the file , read it and then split each line to 3 tokens which will be seperated from the semicolon .... e.g 1;35435;75675 token1 = 1; token2 = 35435; token3 = 75675; the code that i have is a main which i open and read the file and a function which i take manually a string of characters and split it ... I want to know if there is an easier way to implement this and a

问题 I want to find the file in the path known and if it is pre-existing in android then trigger an event(enable/disable canvas) with it. Here is an example I used - public void FileChk(){ string filePath = "file://" + Application.temporaryCachePath + "/" + "folder23" + "/" + fileName; if (!fileName.Exists) { //event } else { //event } } what am I doing wrong here and how do I get this event to trigger when the file exists. 回答1: You can use the System.IO namespace. public void FileChk() { string

问题 I have a text file contains delimited records. 1243;jhhf';982u4k;9u2349;huf8 kij;9238u;98ur23;jfwf;03i24 I need to replace the value of 4th part from every record with the value returned from database or someother source. Any clue ? expecting VB CODE 回答1: Take a look at here( for C# language ); Split string in C# 回答2: You could try this (written in C#): C# release List<string> newLines = new List<string>(); string[] lines = File.ReadAllLines(filename); foreach (string line in lines) { string[