一个变长参数实例

#include
#include

void minprintf(char *fmt, ...)
{
    va_list ap;
    int ival;
    char *p,*sval;
    double dval;
   
    va_start(ap, fmt);
    for (p = fmt; *p; ++p)
    {
        if (*p != '%')
            {
                putchar (*p);
                continue;
            }
            switch (*++p)
            {
                case 'd':
                    ival = va_arg(ap, int);
                    fprintf (stdout, "%d\t", ival);
                    break;
                case 'f':
                        dval = va_arg(ap, double);
                        fprintf (stdout, "%f\t", dval);
                        break;
                case 's':
                    for (sval = va_arg(ap, char *); *sval; ++sval)
                        putchar (*sval);
                putchar ('\t');
                break;
                default:
                    putchar (*p);
                    break;
            }
    }   
    va_end(ap);
}

int main()
{
    int i = 10;
    double d = 3.1415;
    char s[] = "Hello, World!";
    minprintf ("%d\n", i);
    minprintf ("%d\n", d);
    minprintf ("%s\n", s);
    return 0;
}