【面试题】printf函数实现

#include <iostream>#include <stdarg.h>using namespace std;//printf函数的实现int __cdecl cc_printf(    const char *format,    ...){    va_list argulist;    int ret = 0;    va_start(argulist, format);    while (*format)    {if(*format != '%'){putchar(*format);++ret;goto loop;}else{++format;switch (*format){//charcase 'c':{int value = va_arg(argulist, int);ret += printf("%c", (char)value);goto loop;}//char * case 's':{char *value = va_arg(argulist, char *);ret += printf("%s", value);goto loop;}//intcase 'd':{int value = va_arg(argulist, int);ret += printf("%d", value);goto loop;}case 'o':{int value = va_arg(argulist, int);ret += printf("%x", value);goto loop;}case 'x':{int value = va_arg(argulist, int);ret += printf("%x", value);goto loop;}case 'X':{int value = va_arg(argulist, int);ret += printf("%X", value);goto loop;}case 'u':{unsigned value = va_arg(argulist, unsigned);ret += printf("%u", value);goto loop;}case 'f':{double value = va_arg(argulist, double);ret += printf("%f", value);goto loop;}default:{goto loop;}}}loop:++format;    }    va_end(argulist);    return ret;}void main(){int i=10;cc_printf("%d\n",i);cc_printf("hello world\n");}