C语言例程27：命令行變元

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
int main(int argc, char *argv[])
{
    int disp, count;
    if(argc < 2){
        printf("You must enter the length of the count\n");
        printf("on the command line.Try again\n");
        exit(1);
    }

    if(argc == 3 && !strcmp(argv[2], "display"))
        disp = 1;
    else
        disp = 0;
    for(count = atoi(argv[1]); count; --count)
        if(disp)
        printf("%d\n", count);

    putchar('\a');
    printf("Down");
    system("pause");
    return 0;
}