fgets

reading a block of lines in a file using php

由 那年仲夏 提交于 2019-12-18 07:12:10
问题 Considering i have a 100GB txt file containing millions of lines of text. How could i read this text file by block of lines using PHP? i can't use file_get_contents(); because the file is too large. fgets() also read the text line by line which will likely takes longer time to finish reading the whole file. If i'll be using fread($fp,5030) wherein '5030' is some length value for which it has to read. Would there be a case where it won't read the whole line(such as stop at the middle of the

using fgets as non-blocking function c++

由 坚强是说给别人听的谎言 提交于 2019-12-17 21:11:05
问题 I'm writing a program that reads in a loop from the stdin, using the function fgets, as follows: while(fgets(buffer2, BUFFERSIZE , stdin) != NULL){ //Some code } I want my code to be non-blocking, that is: I don't want the program to hold on the 'fgets' line when there's no input at the moment from the user. How can i do it? 回答1: fgets() is a blocking function, it is meant to wait until data is available. If you want to perform asynchronous I/O, you can use select() , poll() , or epoll() .

fgets prompt limited to 1024 Bytes

由 。_饼干妹妹 提交于 2019-12-17 20:32:10
问题 I have been struggling with a pretty simple issue writing a little program in C . Getting input (commands, arguments, flags to be executed) via fgets() works fine as long as the size of the input does not exceed 1024 bytes. After 1024 characters are typed, no more characters are accepted -- the prompt just stops. I assume reason for the problem doesn't lay in the fgets() parameters/configuration because otherwise it would at least take the input up to defined size instead of blocking. How can

Use of undefined constant STDIN - assumed 'STDIN' in C:\wamp\www\study\sayHello.php on line 5

由 拥有回忆 提交于 2019-12-17 16:29:19
问题 I want to Learn php & mySQL and I purchased a book (php&mySql: the missing manuals 2edition) I installed Wampserver2.4 on win8 64bit machine. Server Configuration Apache Version : 2.4.4 PHP Version : 5.4.12 in first lesson i got this error :( Notice: Use of undefined constant STDIN - assumed 'STDIN' in C:\wamp\www\study\sayHello.php on line 5 this is the php code on file "sayHello.php" <?php echo "Hello there. So I hear you're learning to be a PHP programmer!\n"; echo "Why don't you type in

Difference between scanf() and fgets()

由 故事扮演 提交于 2019-12-17 09:19:37
问题 I want to know what is the difference between fgets() and scanf() . I am using C as my platform. 回答1: There are multiple differences. Two crucial ones are: fgets() can read from any open file, but scanf() only reads standard input. fgets() reads 'a line of text' from a file; scanf() can be used for that but also handles conversions from string to built in numeric types. Many people will use fgets() to read a line of data and then use sscanf() to dissect it. 回答2: int scanf(const char *

How to read from stdin with fgets()?

由 白昼怎懂夜的黑 提交于 2019-12-17 07:21:18
问题 I've written the following code to read a line from a terminal window, the problem is the code gets stuck in an infinite loop. The line/sentence is of undefined length, therefore I plan to read it in parts into the buffer, then concatenate it to another string which can be extended via realloc accordingly. Please can somebody spot my mistake or suggest a better way of achieving this? #include <stdio.h> #include <string.h> #define BUFFERSIZE 10 int main (int argc, char *argv[]) { char buffer

c语言中gets ，getschar 和fgets 的用法及三者之间的差别，还有scanf

由 半城伤御伤魂 提交于 2019-12-17 05:11:18
①gets——从标准输入接收一串字符，遇到'\n'时结束，但不接收'\n'，把 '\n'留存输入缓冲区；把接收的一串字符存储在形式参数指针指向的空间，并在最后自动添加一个'\0'。 getchar——从标准输入接收一个字符返回，多余的字符全部留在输入缓冲区。 fgets——从文件或标准输入接收一串字符，遇到'\n'时结束，把'\n'也作为一个字符接收；把接收的一串字符存储在形式参数指针指向的空间，并在'\n'后再自动添加一个'\0'。 简单说，gets是接收一个不以'\n'结尾的字符串，getchar是接收任何一个字符(包括'\n')，fgets是接收一个以'\n'结尾的字符串。 scanf( )函数和gets( )函数都可用于输入字符串，但在功能上有区别。 gets可以接收空格 scanf遇到空格、回车和Tab键都会认为输入结束，所有它不能接收空格 fgets用法： fgets(buf,sizeof(s),stdin)： fgets(buf, n, file) 函数功能：从 目标文件流 file 中读取 n-1 个字符，放入以 buf 起始地址的内存空间中。 楼主的函数调用是这个意思： 首先，s 肯定是一个字符数组。 该调用从 标准输入流 stdin （也就是键盘输入）读入 s 数组的大小(sizeof(s))再减 1 的长度的字符到 buf 所指的内存空间中

Dealing with input in C

由 你离开我真会死。 提交于 2019-12-13 17:38:04
问题 A brief question really, looking for, wondering about, and asking for any tips for what the best way is to handle this type of input: word word word word word word word word word word word whereby the number of words on each line is totally random, and each separate word can be added to some data structure, like a linked list or tree for example. Fgets each line and parse? Getchar()? Any clues? 回答1: Reading one line at a time with fgets seems like the best option here. Then just use strtok or

Getting a single character without pressing enter [duplicate]

由 梦想的初衷 提交于 2019-12-13 14:22:13
问题 This question already has answers here : What is the equivalent to getch() & getche() in Linux? (6 answers) Closed 4 years ago . I'm trying to get a single character input from the user without the user having to press enter. I've tried this: #include <stdio.h> int main() { int input; for (;;) { input = getchar(); printf("%d\n", input); } } But not only does the user need to press enter, it also registers two presses (the input character and the newline character) ie: $ ./tests a 97 10 c 99

Strlen gives an incorrect output after fgets

由 烈酒焚心 提交于 2019-12-13 11:12:51
问题 I read a string using fgets. It prints correctly but if i try to output the length using a strlen or a while until NULL it returns a bad value. Does fgets not end the string with NULL? char word[256]; fgets(word, sizeof(word), stdin); while(word[i]) i++; printf("%d",i); For the string aba it outputs 40. 回答1: Function fgets also includes the new line character in the string. So function strlen counts this symbol. From the C Standard 2 The fgets function reads at most one less than the number
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