In this article, we’ll take a look at using the system(“pause”) command in C++.

在本文中，我们将介绍如何在C ++中使用system（“ pause”）命令。

Before going through this article, note this the system("pause") command is only available in Windows Systems.

在阅读本文之前，请注意，此system("pause")命令仅在Windows系统中可用。

This means that you cannot use this from any Linux / Mac machine.

这意味着您不能在任何Linux / Mac计算机上使用它。

system（）命令 (The system() command)

Before going through the system(“pause”) command, let’s understand what system() does.

在执行system（“ pause”）命令之前，让我们了解一下system()作用。

#include <cstdlib>int system(const char *command);

The system() function performs a call to the Operating System to run a particular command.

system()函数执行对操作系统的调用以运行特定命令。

Note that we must include the <cstdlib> header file.

注意，我们必须包括<cstdlib>头文件。

This is very similar to opening a terminal and executing that command by hand.

这与打开终端并手动执行该命令非常相似。

For example, if you want to use the “ls” command from Linux, you can use system("ls").

例如，如果要在Linux中使用“ ls”命令，则可以使用system("ls") 。

If you are having any Linux/Mac machine, you can try the below code.

如果您有任何Linux / Mac计算机，则可以尝试以下代码。

#include <iostream>
#include <cstdlib>using namespace std;int main() {// Try the "ls -l" command from your Linux / Mac machineint ret = system("ls -l > test.txt");return 0;
}

Possible Output

可能的输出

total 16
-rwxr-xr-x 1 2001 2000 9712 Jun 25 21:11 a.out
-rw-rw-rw- 1 2001 2000  209 Jun 25 21:11 main.cpp
-rw-r--r-- 1 2001 2000    0 Jun 25 21:11 test.txt

Now that we’re a bit clear on what system() can do, let’s look at the system(“pause”) command.

现在我们对system()可以做什么有了一个清晰的认识，让我们看一下system（“ pause”）命令。

在C ++中使用system（“ pause”）命令 (Using system(“pause”) command in C++)

This is a Windows-specific command, which tells the OS to run the pause program.

这是Windows特定的命令，它告诉OS运行pause程序。

This program waits to be terminated, and halts the exceution of the parent C++ program. Only after the pause program is terminated, will the original program continue.

该程序等待终止，并停止执行父C ++程序。 仅在暂停程序终止后，原始程序才会继续。

If you’re using a Windows machine, you can run the below code:

如果您使用的是Windows计算机，则可以运行以下代码：

#include <iostream>
#include <cstdlib>using namespace std;int main() {for (int i=0; i<10; i++) {cout << "i = " << i << endl;if (i == 5) {// Call the pause commandcout << "Calling the pause command\n";system("pause");cout << "pause program terminated. Resuming...\n";}}return 0;
}

Output – From Windows System

输出–从Windows系统

i = 0
i = 1
i = 2
i = 3
i = 4
i = 5
Calling the pause command
Press any key to continue . . .
pause program terminated. Resuming...
i = 6
i = 7
i = 8
i = 9E:\Programs\sample.exe (process 14052) exited with code 0.

As you can observe, the pause command was indeed executed when our if condition i = 5.

如您所见，当if条件i = 5时，确实执行了stop命令。

After we hit enter, we terminated the pause program, and resumed our loop in C++ program!

按下回车键后，我们终止了暂停程序，并在C ++程序中恢复了循环 ！

使用system（“ pause”）命令的缺点 (Disadvantages of using the system(“pause”) command)

The main pitfall of system(“pause”) is that this is platform specific. This does not work on Linux/Mac systems, and is not portable.

系统的主要陷阱（“暂停”）是特定于平台的。 这在Linux / Mac系统上不起作用，并且不可移植。

While this works as a kind of a hack for Windows systems, this approach may easily cause errors, when you try to run the code on other systems!

尽管这对于Windows系统是一种黑客手段，但是当您尝试在其他系统上运行代码时，这种方法很容易导致错误！

Therefore, I would suggest some other alternative ways to pause and resume a program, such as using signal handlers.

因此，我建议使用其他替代方法来暂停和恢复程序，例如使用信号处理程序。

结论 (Conclusion)

In this article, we learned how we could use the system(“pause”) command in C++. For similar content, do go through our tutorial section on C++ programming!

在本文中，我们学习了如何在C ++中使用system（“ pause”）命令。 对于类似的内容，请阅读我们有关C ++编程的教程部分 ！

参考资料 (References)

• cppreference.com page on system() in C++C ++中system（）上的cppreference.com页面

翻译自: https://www.journaldev.com/41740/system-pause-command-c-plus-plus