stdio

问题 One cool feature of netcat is how it can turn any command line program into a server. For example, on Unix systems we can make a simple date server by passing the date binary to netcat so that it's stdout is sent through the socket: netcat -l -p 2020 -e date Then we can invoke this service from another machine by simply issuing the command: netcat <ip-address> 2020 Even a shell could be connected ( /bin/sh ), although I know this is highly unrecommended and has big security implications.

问题 I am wondering why does the following code not work as expected: #include <iostream> #include <string> using namespace std; int main(){ int n; string s; //scanf("%d",&n); cin >> n; ios_base::sync_with_stdio(false); cin >> s; cout << n << " " << s; return 0; } Input: 10 abcd Output: 10 The string is not getting printed! The result is same if I use scanf to input the integer. However, the code does work as expected if the line ios_base::sync_with_stdio(false); is placed before the first cin (or

问题 I wrote the following C code: #include<stdio.h> int main(){ printf("A"); if(fork() == 0){ printf("B"); } else{ printf("C"); } } The output I got is: ACAB I expected this code to print A only once. Can anyone explain this output? 回答1: Your error is not flushing the buffers before fork -ing, thus both processes will write it. Add this before fork() : fflush(0); // Flush all output-streams 回答2: The 'A' is stored in a buffer and flushed by both processes when they exit. 来源： https://stackoverflow

问题 I wrote the following C code: #include<stdio.h> int main(){ printf("A"); if(fork() == 0){ printf("B"); } else{ printf("C"); } } The output I got is: ACAB I expected this code to print A only once. Can anyone explain this output? 回答1: Your error is not flushing the buffers before fork -ing, thus both processes will write it. Add this before fork() : fflush(0); // Flush all output-streams 回答2: The 'A' is stored in a buffer and flushed by both processes when they exit. 来源： https://stackoverflow

问题 I wrote a program that reads a binary file, does some process with its contents and writes the results to a different file. In Linux it works perfectly, but in Windows it does not work; the output files are always 1KB... This is a simplified version of the program: #include <stdio.h> void copyFile(char* source, char* dest); int main (int argc, char* argv[]) { if (argc != 3) printf ("usage: %s <source> <destination>", argv[0]); else { copyFile(argv[1], argv[2]); } } void encryptFile(char*

问题 I wrote a program that reads a binary file, does some process with its contents and writes the results to a different file. In Linux it works perfectly, but in Windows it does not work; the output files are always 1KB... This is a simplified version of the program: #include <stdio.h> void copyFile(char* source, char* dest); int main (int argc, char* argv[]) { if (argc != 3) printf ("usage: %s <source> <destination>", argv[0]); else { copyFile(argv[1], argv[2]); } } void encryptFile(char*

问题 As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance. Closed 7 years ago . As a newb, like myself, to have great difficulty with searching the header files such as stdio.h for a function like getchar().

问题 In C, I want to create and open text files to write data into, but the problem is I want to name the files on the go, such as FILE *ptr; for(i=0;i<1000;i++){ fopen_s(&ptr,"i.txt","w"); operations to fill data into file i.txt; fclose(ptr); } such that I will create file 0.txt, 1.txt, 2.txt ... 999.txt. How is this possible? I checked open and rename functions, but couldn't find a way to do. Thank you so much for all your help. Best, 回答1: use snprintf to set the file number: FILE *ptr; char

问题 I think about adding possibility of using same the filename for both input and output file to my program, so that it will replace the input file. As the processed file may be quite large, I think that best solution would to be first open the file, then remove it and create a new one, i.e. like that: /* input == output in this case */ FILE *inf = fopen(input, "r"); remove(output); FILE *outf = fopen(output, "w"); (of course, with error handling added) I am aware that not all systems are going

问题 I'm trying to read a return delimited file. full of phrases. I'm trying to put each phrase into a string. The problem is that when I try to read the file with fscanf(file,"%50s\n",string); the string only contains one word. when it bumps with a space it stops reading the string 回答1: fscanf can be modified to read past spaces. The details are a bit complicated. Here is what the man page says about %[...] Matches a nonempty sequence of characters from the specified set of accepted characters;