getopt（分析命令行参数）

#include <stdio.h>
#include <unistd.h>

int main(int argc, int *argv[])
{
        int ch;
        opterr = 0;
        while ((ch = getopt(argc,(char* const*)argv,"a:b::cde"))!=-1)
        {
                switch(ch)
                {
                        case ‘a‘:
                                printf("option a:‘%s‘\n",optarg);
                                break;
                        case ‘b‘:
                                printf("option b :b\n");
                                break;
                        default:
                                printf("other option :%c\n",ch);
                }
        }
        printf("optopt +%c\n",optopt);
}