执行
C语言程序需要先编译再运行。本教程不涉及较为底层的编译原理与中间过程。
编译
如果你对C语言的具体编译过程感兴趣，可以看看以下外部资料：
在您的设备上配置C/C++语言的开发环境，请参见安装章节。
在大多数情况下，例如在Windows上使用MinGW、在Linux上使用gcc，你都可以使用如下命令对单个文件进行快速编译：
bash
gcc [source.c] -o [program] // gcc编译C语言源文件
g++ [source.cpp] -o [program] // g++编译C++源文件此命令会将源文件source.c或source.cpp编译并最终生成名为program的可执行程序，然后你可以在终端中运行program程序。下面给出一个使用C++语言的简单的示范：
cpp
#include <iostream>
using namespace std;
class Vehicle {
protected:
int MaxSpeed;
int Weight;
public:
Vehicle(int m, int w) {
MaxSpeed = m;
Weight = w;
cout << "Constructing Vehicle...\n";
}
~Vehicle() {
cout << "Destructing Vehicle...\n";
}
void Run() {
cout << "The vehicle is running!\n";
}
void Stop() {
cout << "Please stop stopped!\n";
}
void Show() {
cout << "It\'s maxspeed is:" << MaxSpeed << endl;
cout << "It\'s widget is:" << Weight << endl;
}
};
class Bicycle : virtual public Vehicle {
protected:
int Height;
public:
Bicycle(int m, int w, int h) : Vehicle(m, w) {
Height = h;
cout << "Constructing Bicycle...\n";
}
~Bicycle() {
cout << "Destructing Bicycle...\n";
}
void Show() {
Vehicle::Show();
cout << "It\'s height is:" << Height << endl;
}
};
class Car : virtual public Vehicle {
protected:
int SeatNum;
public:
Car(int m, int w, int s) : Vehicle(m, w) {
SeatNum = s;
cout << "Constructing Car...\n";
}
~Car() {
cout << "Destructing Car...\n";
}
void Show() {
Vehicle::Show();
cout << "It\'s seatnum is:" << SeatNum << endl;
}
};
class MotorCycle : public Bicycle, public Car {
public:
MotorCycle(int m, int w, int h, int s) : Vehicle(m, w), Bicycle(m, w, h), Car(m, w, s) { // [16]
cout << "Constructing MotorCycle...\n";
}
~MotorCycle() {
cout << "Destructing MotorCycle...\n";
}
void Show() {
cout << "It\'s maxspeed is:" << MaxSpeed << endl;
cout << "It\'s widget is:" << Weight << endl;
cout << "It\'s height is:" << Height << endl;
cout << "It\'s seatnum is:" << SeatNum << endl;
}
};
int main() {
MotorCycle mc(10, 20, 30, 40);
mc.Run();
mc.Stop();
mc.Show();
return 0;
}bash
g++ test_2_5.cxx -o test_2_5文件拓展名cxx与cpp实质上并无区别。现在，在该目录下将出现名为test_2_5的文件。运行它：
bash
> ./test_2_5
Constructing Vehicle...
Constructing Bicycle...
Constructing Car...
Constructing MotorCycle...
The vehicle is running!
Please stop stopped!
It's maxspeed is:10
It's widget is:20
It's height is:30
It's seatnum is:40
Destructing MotorCycle...
Destructing Car...
Destructing Bicycle...
Destructing Vehicle...运行
编译完成后得到可执行文件，执行即运行了编译的代码。
对于单源码文件编译成的程序来说，程序的入口是main函数。对于多文件编译而成的程序，编译一个可执行程序用到的所有源文件中只能存在一个main函数作为入口。C语言中，main函数需要以如下方式定义：
c
int main(void) {
// 一些代码
return 0;
}在后面的教程中会涉及到函数的有关概念。main函数是允许没有形参、返回整形类型的函数，其返回值将会作为程序进程结束时的返回值，0表示程序正常结束，任何非0的值都意味着错误。
如果想要了解如何编译并运行多文件项目，请参见C语言或C++教程的后面内容，以及CMake章节的教程。
MangoFanFan_