如何将程序的输出显示到文件和控制台（stdout）？(How to display the output of a program both to a file and to the console(stdout)?)

 假设我有以下程序只输出“Hello World”： 
 
//DEMO.c
#include<stdio.h>

int main()
{
printf("HELLO World");
}
 
 现在我想将它显示在屏幕和文件output.txt 。所以我在命令提示符下输入以下命令（我在Windows XP上使用CodeBlocks并将其配置为在命令提示符下工作）： 
 
 demo.exe>>output.txt>>stdout 
 
 它不起作用！ 请告诉我怎么做，即如何输出我在屏幕上看到的同样的东西（当我运行程序时），同时输出到文本文件？ 

Say I have the following program that simply outputs "Hello World":
 
//DEMO.c
#include<stdio.h>

int main()
{
printf("HELLO World");
}
 
Now I want to display it both to the screen and to a file output.txt.So I enter the following command in the command prompt(I use CodeBlocks on Windows XP and have configured it to work on command prompt as well):
 
demo.exe>>output.txt>>stdout
 
It doesn't work!!! Please tell me how to do it,ie how to output the same thing that I see on my screen(When i run the program),simultaneously to a text file?

原文：https://stackoverflow.com/questions/16165854