1. Introduction
If you know something about Unix/Linux, you should know that most of them come with their own compilers for C and C++, namely GCC and G++. Unix uses these compilers in many places such as program installation and Make. Using some console commands, C++ and PHP, I will show you how to generate a complete C++ program example that can be executed in a PHP program and get the corresponding output results. I will first generate the C++ program code, compile it, and then discuss how we will execute this program by using the PHP function passthru. In a sense, this article provides us with a way to access general programs through Web pages.
In order to better understand this article, you should have a unix/Linux server running apache and the latest version of php. At the same time, you should also master C++ and unix console commands. Of course, some PHP programming experience is also required.
2. Write a C++ program
For example, we can write a program that can also receive parameters through the command line. C++ simple program, named Sampleapp. Then we can pass it three different parameters in the following way:
Sampleapp? Parameter one? Parameter two? Parameter three
The function of this program is to output the number of parameters passed to it and the value of each parameter. Then we can use a PHP script program to execute the compiled C++ program.
Use your favorite text editor to create a new file named Sampleapp.cpp, and enter the following code into this file:
#include
int main(int argc, char* argv[])
{
cout << endl << "You passed " << argc-1 << " argument"
<< (argc-1 == 1 ? "" : "s") << "." " argument" << (argc-1 == 1 ? "" : "s") << " "
<< (argc-1 == 1 ? "is" : " are") << ": " << endl << endl;
for(int i = 1; i < argc; i++)
cout << "[" << i << "] " << argv[i] << endl;
return 0;
} This C++ program contains the entry point of the program: main(). The main() function takes two parameters: argc (the number of parameters passed in from the command line) and argv( An array of character pointers containing the actual values of the parameters passed). These two parameters can be automatically captured by the C++ compiler.
cout << endl << "You passed " << argc-1 << " argumentation"
<< (argc- 1 == 1 ? "" : "s") << "." << endl;;
This sentence means to get the command line from execution The number of parameters entered. The character pointer array Argv is retrieved starting from 0. It contains at least one actual value (that is, the path and name of this program). This value is automatically appended by the C++ compiler. The conditional operator "?" is used to determine whether there is more than one parameter passed in from the command line. For example, if two parameters are passed in from the command line, our program will output the following information:
You passed 2 arguments. << (argc-1 == 1 ? "This" : "These")
<< " argumentation" << (argc-1 == 1 ? "" : "s ") << " "
<< (argc-1 == 1 ? "is" : "are") << ": " << endl << endl;
Next, we also use conditional operators to output another sentence. But remember, even if we don't pass in any parameters from the program execution command line, the argv[] parameter of the main function contains a value. Similarly, if we pass two parameters to the program from the command line, the program will output the following information:
> for(int i = 1; i < argc; i++)
cout << "[" << i << "] " << argv[i] < ;< endl;
Finally, the main function outputs each parameter passed in from the command line one by one. It uses a simple for(;;) loop statement. This function can The parameter values are output one by one according to the number of parameters. If we pass two parameters "first" and second" to the program, the output result of the for loop is as follows:
[1] ?first
[2] ?second
The above is a brief description of this C++ program. Its function is very simple, which is to display the parameters passed in from the command line on the output screen using the cout function. >
Next, we will compile this .cpp file. If you are on the Windows platform, you need to telnet to the server you are using. Here, we use the G++ compiler provided on most Unix machines to compile this source file. But to make sure that your machine has G++ installed, you can enter the following command: which g++. If G++ is already installed, the Unix shell will display the full path to where G++ is located. If it is not installed, it will prompt you saying "command couldn't be found". You can download G++ here.Enter the following G++ command in the directory where the source file is located:
g++ -c sampleapp.cpp.
With this command, we compile the .cpp file into a target file containing machine code. Through the ls ?a command, you can find that a new file sampleapp.o appears in this directory. This is the result of the .cpp source file being compiled into machine code. But what we ultimately want is an executable file, because we also need to enter the following G++ command:
g++ sampleapp.cpp ?o sampleapp
In this way we obtain an executable file named sampleapp. However, please note that the executable file under Unix is different from Windows, it does not have any suffix.
Now we can check the results of program execution. If the following command is given:
sampleapp one -two /three
We can See the following execution results:
You passed 3 arguments.
These arguments are:
[2] ?two [3] /three
Now that the executable C++ program is generated, below we will generate a program that can be accessed through a web browser Access this program's PHP tutorial.
3. Generate PHP script program
In order to call our C++ program through the Internet, we need to generate a PHP script program. This PHP script will have a Form so that the user can enter parameters that can be passed to the Sampleapp program. The code of the PHP script is too long so I won’t list it all here. If necessary, you can download it from the address below. (Php code)
if(@$submit) { } else { }
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