1 示例程序

在这里展示一个的示例程序，该程序接收输入的三个参数，并将这三个参数打印出来。

示例程序的代码（rec_user_arg.cpp）内容如下：

#include <iostream>
#include <string.h>
using namespace std;
void ShowUsage()
{
    cout << "Usage   : rec_user_arg <--name=your name> [Option]" << endl;
    cout << "Options :" << endl;
    cout << " --name=your name                  Your name, this option MUST be given." << endl;
    cout << " --occupation=your occupation      Your occupation, such as paladin." << endl;
    cout << " --camp=your camp                  Your camp, such as alliance." << endl;
    cout << " --help                            Print this help." << endl;
    return;
}
int main(int argc, char *argv[])
{
    // 如果用户没有输入参数，则提示错误信息并退出
    if (argc < 2)
    {
        cout << "No arguments, you MUST give an argument at least!" << endl;
        ShowUsage();
        return -1;
    }
    int nOptionIndex = 1;
    string strName;
    string strOccupation;
    string strCamp;
    while (nOptionIndex < argc)
    {
        // 获取用户姓名
        if (strncmp(argv[nOptionIndex], "--name=", 7) == 0)
        {
            strName = &argv[nOptionIndex][7];
        }
        // 获取用户职业
        else if (strncmp(argv[nOptionIndex], "--occupation=", 13) == 0)
        {
            strOccupation = &argv[nOptionIndex][13];
        }
        // 获取用户阵营
        else if (strncmp(argv[nOptionIndex], "--camp=", 7) == 0)
        {
            strCamp = &argv[nOptionIndex][7];
        }
        // 显示帮助信息
        else if (strncmp(argv[nOptionIndex], "--help", 6) == 0)
        {
            ShowUsage();
            return 0;
        }
        else
        {
            cout << "Options '" << argv[nOptionIndex] << "' not valid. Run '" << argv[0] << "' for details." << endl;
            return -1;
        }
        nOptionIndex++;
    }
    cout << "Name is: " << strName << endl;
    cout << "Occupation is: " << strOccupation << endl;
    cout << "Camp is: " << strCamp << endl;
    return 0;
}