stdin

问题 I get how to open files, and then use Python's pre built in functions with them. But how does sys.stdin work? for something in sys.stdin: some stuff here lines = sys.stdin.readlines() What's the difference between the above two different uses on sys.stdin? Where is it reading the information from? Is it via keyboard, or do we still have to provide a file? 回答1: So you have used Python's "pre built in functions", presumably like this: file_object = open('filename') for something in file_object:

问题 I have to do an assignment where I have to write a C-Programm, where it gets the input-file-name from the console as command line parameter. It should move the data from the input.txt file (the input file has the information for the bmp file - color etc.) to the generated output.png file. The 20 20 parameters stand for width and height for the output.png image. So the console-request for example (tested on Linux) will look like this: ./main input.txt output.bmp 20 20 I know that this code

问题 I am trying to receive data via stdin which I have working: const fs = require('fs'); const readStream = process.stdin; readStream.pause(); readStream.setEncoding('utf8'); readStream.on('data', (data) => { console.log(data); }); readStream.resume(); Now what I need to do is store it as a variable so I can do some calculations before I return it via stdout. Every time I try to so anything with it, like push certain data to an array it repeats the data until the stdin has finished, and I cant

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

问题 I am using the following code: #include <iostream> using namespace std; int main(int argc, char **argv) { string lineInput = " "; while(lineInput.length()>0) { cin >> lineInput; cout << lineInput; } return 0; } With the following command: echo "Hello" | test.exe Thes result is an infinate loop printing "Hello". How can I make it read and print a single "Hello"? 回答1: string lineInput; while (cin >> lineInput) { cout << lineInput; } If you really want full lines, use: string lineInput; while

问题 My Ruby program reads lines from stdin and uses puts to print to stdout (the terminal). Can I use RSpec to test the reads and writes? Can I inject a string to my program like it was written in stdin and at the same time check the output? line = STDIN.read.chomp.split Also, I have the reads and writes in a loop, until line[0] is "quit". Can I test while the loop is running or should I call subject.read_in and subject.write_out ? 回答1: You can use mocks and have the method called more than once

问题 What are the possible ways for reading user input using read() system call in Unix. How can we read from stdin byte by byte using read() ? 回答1: You can do something like this to read 10 bytes: char buffer[10]; read(STDIN_FILENO, buffer, 10); remember read() doesn't add '\0' to terminate to make it string (just gives raw buffer). To read 1 byte at a time: char ch; while(read(STDIN_FILENO, &ch, 1) > 0) { //do stuff } and don't forget to #include <unistd.h> , STDIN_FILENO defined as macro in

问题 I am reading bunch of integers separated by space or newlines from the standard in using Scanner(System.in) . Is there any faster way of doing this in Java? 回答1: Is there any faster way of doing this in Java? Yes. Scanner is fairly slow (at least according to my experience). If you don't need to validate the input, I suggest you just wrap the stream in a BufferedInputStream and use something like String.split / Integer.parseInt . A small comparison: Reading 17 megabytes (4233600 numbers)

问题 I basically want to test if stdin has input (like if you echo and pipe it). I have found solutions that work, but they are ugly, and I like my solutions to be clean. On linux I use this: bool StdinOpen() { FILE* handle = popen("test -p /dev/stdin", "r"); return pclose(handle) == 0; } I know that I should add more error handling, but it's besides the point. On windows I use this: bool StdinOpen() { static HANDLE handle = GetStdHandle(STD_INPUT_HANDLE); DWORD bytes_left; PeekNamedPipe(handle,

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