fgets

Searching for strings that are NULL terminated within a file where they are not NULL terminated

由 大兔子大兔子 提交于 2019-12-25 08:58:33
问题 I am writing a program that opens two files for reading: the first file contains 20 names which I store in an array of the form Names[0] = John\0 . The second file is a large text file that contains many occurences of each of the 20 names. I need my program to scan the entirity of the second file and each time it finds one of the names, a variable Count is incremented and so on the completion of the program, the total number of all the names appearing in the text is stored in Count . Here is

Linux Redirection to C program - File Reading

由 孤人 提交于 2019-12-25 07:48:33
问题 I want to read lines of numbers from the text file ( filename.txt ) using a function in C. How do I open this file (provided the filename is only given through a redirection on Unix)? i.e. ./cfile < filename.txt int main (void) { char filename[20]; fgets(filename, 19, stdin); FILE *fp; fp = fopen(filename, "r"); } So, would this be correct; also, how do I access one line at a time from the file (all I know is EOF has to be used somewhere)? 回答1: The contents of filename.txt gets redirected to

How to use select to read input from stdin?

由 别说谁变了你拦得住时间么 提交于 2019-12-25 07:04:59
问题 I am trying to read from stdin using select , after that I am sending the data through a socket to a server. The following snippet is supposed to follow the above logic; but it doesn't read anything from stdin . Moreover it prints Enter command: after the first time the user inputs a string. The line printf("%d %s\n",__LINE__ ,buf); doesn't print anything as either. fd_set rfds; struct timeval tv; int retval; char buf[BUFLEN]; while(1) { FD_ZERO(&rfds); FD_SET(STDIN_FILENO, &rfds); tv.tv_sec

how to use fgets and sscanf for integers in loop

由 主宰稳场 提交于 2019-12-25 05:35:49
问题 Beginner with C here. I am trying to run a loop where strings and ints are entered into various fields of a struct . When prompted for a 'last name', the user can press enter with no other input and the loop should end. The problem is that with this code, the loop doesnt end (last name and first name entry requests run together on the same line) and the value for salary always comes out wrong (0 or some large number) while (employee_num <= 2) { printf("Enter last name "); fgets(employee

How to process CSV lines with nul char in some elements?

由 早过忘川 提交于 2019-12-25 03:47:30
问题 When reading and parsing a CSV-file line, I need to process the nul character that appears as the value of some row fields. It is complicated by the fact that sometimes the CSV file is in windows-1250 encoding, sometimes it in UTF-8, and sometimes UTF-16. Because of this, I have started some way, and then found the nul char problem later -- see below. Details: I need to clean a CSV files from third party to the form common to our data extractor (that is the utility works as a filter --

Using “gets” for String input in C

由 陌路散爱 提交于 2019-12-25 02:22:38
问题 I have been trying to get a string input from a user using fgets but fgets does not wait for input so upon investagation I learned of the gets function which seems to be working fine. My questions are: 1. Why does gets work when I input more than 10 characters if I declared an array of only ten elements. Here is my code #include<stdio.h> int main(void){ char name[10]; printf("Please enter your name: "); gets(name); printf("\n"); printf("%s", name); return 0; } my input when testing:

Last line repeats when doing fgets/fputs

由 只谈情不闲聊 提交于 2019-12-24 21:17:41
问题 I'm doing an insertion, that imply a file , a string , and a new file who will receive all the data of the original file plus the string to be inserted , and it will replace the original file. So, for example, my original file: data.txt line1 line2 line3 line4 line5 will become, with the insertion of the string "newline": data_temp.txt --> renamed later data.txt line1 line2 line3 line4 line5 newline With that purpose, I have the following code: /* FILE variables of the original file and the

PHP and Importing pylab

由 无人久伴 提交于 2019-12-24 20:41:09
问题 I have a PHP script that calls in a python program. Here is the php script: <?php $last_line = popen('/Library/Frameworks/Python.framework/Versions/Current/bin/python test.py', 'r'); $results = fgets($last_line); print $results; ?> and this is the content of test.py: test.py: import numpy as np from matplotlib.patches import Ellipse # import matplotlib.pyplot as plt # from matplotlib.pyplot import figure, show # import pylab print "Hello World!" Now, this works fine and I get "Hello World!"

How to read multiple lines of input from user using fgets and write it into a file using fputs in C?

由 試著忘記壹切 提交于 2019-12-24 12:21:56
问题 I wanted to read input from user (multiple lines) and write it into a file using fputs(). Here is my code #include<stdio.h> #include<stdlib.h> int main() { FILE *fp; char s[25]; fp=fopen("myname","w"); if(fp==NULL) { perror("Error opening file\n"); exit(1); } while(fgets(s,25,stdin)!=NULL) fputs(s,fp); fclose(fp); return 0; } After getting input from user, i am using Ctrl+C to close the input prompt of the program (I'm using linux). Then if i open the file, it contains nothing. How could I

C语言文件操作详解

由 亡梦爱人 提交于 2019-12-24 12:07:05
C语言文件操作详解 数据流 数据流（data stream）是一组有序，有起点和终点的字节的数据序列。包括输入流和输出流。 程序与数据的交互是以流的形式进行的。进行C语言文件的存取时，都会先进行“打开文件”操作，这个操作就是在打开数据流，而“关闭文件”操作就是关闭数据流。 缓冲区 指在程序执行时，所提供的额外内存，可用来暂时存放做准备执行的数据。它的设置是为了提高存取效率，因为内存的存取速度比磁盘驱动器快得多。 C语言中带缓冲区的文件处理： C语言的文件处理功能依据系统是否设置“缓冲区”分为两种：一种是设置缓冲区，另一种是不设置缓冲区。由于不设置缓冲区的文件处理方式，必须使用较低级的I/O函数(包含在头文件io.h和fcntl.h中)来直接对磁盘存取，这种方式的存取速度慢，并且由于不是C的标准函数，跨平台操作时容易出问题。下面只介绍第一种处理方式，即设置缓冲区的文件处理方式： 当使用标准I/O函数(包含在头文件stdio.h中)时，系统会自动设置缓冲区，并通过数据流来读写文件。 当进行文件读取时，不会直接对磁盘进行读取，而是先打开数据流，将磁盘上的文件信息拷贝到缓冲区内，然后程序再从缓冲区中读取所需数据，如下图所示： 事实上，当写入文件时，并不会马上写入磁盘中，而是先写入缓冲区，只有在缓冲区已满或“关闭文件”时，才会将数据写入磁盘，如下图所示： fopen、fclose fopen
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