本节讲述如何在终端去编译和运行程序，以及C++的执行过程，参考下面两个图：
执行过程分成三步：
- 预编译，将带有预编译符号比如#include #define的代码，变成纯C++代码(不含预编译符的)
- 编译：将上面预编译之后的输出处理成obj文件，这个文件机器能够识别。
- 链接：将上面编译后的所有obj文件组合起来，生成lib或是可执行的exe文件等。
In summary to compile in a terminal:
- Open a terminal window
- change the working directory to the directory of the program
- Make sure names of folders and files do not have spaces in them
- To compile the program: g++ filename.cpp -o executableName
- To execute the program: ./executableName
Common mistakes when executing in the terminal:
- Make sure there are no spaces in filenames
- Make sure all the files you need are in the working directory (including header files), use ‘ls’ to check
#include <iostream>
#include <stdio.h>
int main()
{
int userInput = 0;
int maxNumber = 0;
int minNumber = 100;
int sumTotal = 0;
float average = 0;
//get the numbers from the user
for(int i = 0; i < 15; i++)
{
std::cout << "Enter a number: ";
scanf("%d", &userInput);
std::cout << userInput << "\n";
if(userInput > maxNumber)
{//the biggest number entered so far is the max number
maxNumber = userInput;
}
if(userInput < minNumber)
{//the lowest number entered so far is the min number
minNumber = userInput;
}
sumTotal = sumTotal + userInput;
}
std::cout << "Maximum number = " << maxNumber << "\n";
std::cout << "Minimum number = " << minNumber << "\n";
average = sumTotal / 15;
std::cout << "Average = " << average << "\n";
return 0;
}
Enter a number: 123
Enter a number: 2
Enter a number: 34
Enter a number: 6
Enter a number: 57
Enter a number: 9
Enter a number: 876
Enter a number: 90
Enter a number: 11
Enter a number: 23
Enter a number: 876
Enter a number: 4
Enter a number: 13
Enter a number: 87