c++ primer 5th教给我的小技巧：
usinng the file redirection.
It can be tedious to repeatedly type these transactions as input to the program you are testing . Most OS support file redirection , which let us associate a named file with the standard input and the standard output , for example :
(the test is a program that can run under linux)
test.cpp
#include <iostream>
using namespace std;
int main()
{
int a;
while ( cin >> a)
{
cout << a;
}
return 0;
}
g++ -o test test.cpp
新建一个输入文件：nano input /nano为linux新建文件的一个命令，nano也是一个行编辑器/
在input文件中输入：
1 2 3 4 5
新建一个输出文件：nano output
运行程序：./test output
打开output看一下里面的内容：nano output
12345
OK.这里要注意的就是使用重定向的时候，输入文件外面的两个尖括号不能少。