#include <stdio.h>#include <stdarg.h>extern char* baseconv(unsigned int,int); //格式化数字void miniprintf(const char *fmt,...){    const char* p;    int i;    unsigned u;    char* s;    va_list argp;    va_start(argp,fmt);    for(p=fmt;*p!=‘\0‘;p++)    {        if(*p!=‘%‘)        {            putchar(*p);            continue;        }                switch(*++p)        {            case ‘c‘:                i=va_arg(argp,int);//“默认参数提升”规则,在可变参数部分                putchar(i);                break;            case ‘d‘:                i=va_arg(argp,int);                if(i<0)                {                    i=-i;                    putchar(‘-‘);                }                fputs(baseconv(i,10),stdout);                break;            case ‘o‘:                u=va_arg(argp,unsigned int);                fputs(baseconv(u,8),stdout);                break;            case ‘s‘:                s=va_arg(argp,char*);                fputs(s,stdout);                break;            case ‘u‘:                u=va_arg(argp,unsigned int);                fputs(baseconv(u,10),stdout);                break;            case ‘x‘:                u=va_arg(argp,unsigned int);                fputs(baseconv(u,16),stdout);                break;            case ‘%‘:                putchar(‘%‘);                break;        }    }    va_end(argp);}

va_arg(argp,var_Type);