自定义打印输出函数格式，模拟printf函数

/*************************************************************  
    FileName : testPrintfFunction.cpp
    FileFunc : printf参数模拟 
    Version  : V0.1  
    Author   : Sunrier  
    Date     : 2011-08-29
	Descp	 : 简单模拟printf函数
*************************************************************/
#include  
#include 
#include //itoa()......
#include 
#include 
#include 


#define		MAXBUF		15

#define		DEFAULT_PRECI		3	//符点型默认精度
 
 
int add(const int ,...);

int myPrintf(const char *, ...);

void ftoa(double InputData, char *OutputData,int  DEFAULT_Vaule);

int main ( void )
{	
	int x,y;

	//int x1=0xFEd278df;
	int x1=8989;
	double doubleData=89.78623;
	
	int x3=0;
	char *s1="1234567";
	
	x = add(4,1,2,3,4);

	y = add(3,1,2,3);

	printf("x=%B\n",x);

	printf("y=%3\n",y); 

	myPrintf("Hello Sunrier!\n");

	myPrintf("wwwwwwwww");

	myPrintf("%s\n",s1);

	myPrintf("x3=%x\n",x3);

	myPrintf("x=%b\n",x);
	printf("x1=%b\n",x1);
	myPrintf("x1=%b\n",x1);

	myPrintf("x1=0x%x s=%s y=%d\n",x1,s1,y);

	myPrintf("doubleData=%f\n",doubleData);
	myPrintf("doubleData=%3f\n",doubleData);
	printf("doubleData=%3f\n",s1);
		
	return 0;
}
 


int add(const int n,...)
{
	va_list arg;//定义va_list类型变量arg

	va_start(arg,n);//arg初始化,n是第一个可见参数名字;使arg指向第一个可选参数
	
	int sum=0;
	int tmp =0;
	for(int i=0;iulValue )
							{
								ucLen = ucI;
								break;
							}
						}
						
						
						for( ucI=0;ucI=0) && (*str<=9) )
							{
								putchar((*str+48));
							}
							else
							{
								putchar((*str+87));
							}
						}
						++format;
						break;
			case	'X':
						offset = 0;
						ucLen = 0 ;
						ulValue=va_arg(ap,const int);
						memset(buf,0,sizeof(buf));

						
						if( !ulValue )
						{
							buf[ucLen] = ulValue ;
							str = buf ;
							putchar((*str+48));
							++format;
							break;
						}

						for( ucI=0;ucIulValue )
							{
								ucLen = ucI;
								break;
							}
						}
						
						
						for( ucI=0;ucI=0) && (*str<=9) )
							{
								putchar((*str+48));
							}
							else
							{
								putchar((*str+55));
							}
						}
						++format;
						break;
			case	'f':
						fdata = va_arg(ap, double);
						memset(buf,0,sizeof(buf));
						ftoa(fdata, buf, DEFAULT_PRECI);
						for (str=buf ;*str!='\0'; str++) 
						{
							putchar(*str);
						}
						++format;
						break;
			case	'.':
						if( isdigit(*++format) )
						{
							if( 'f'==(*++format) )
							{
								--format;
								fdata = va_arg(ap, double);
								memset(buf,0,sizeof(buf));
								int preci =*format-'0'; 
								ftoa(fdata, buf, preci);
								for (str=buf ;*str!='\0'; str++) 
								{
									putchar(*str);
								}
								++format;
								++format;
							}
						}
						else
						{
							--format;
							if( 'f'==(*++format) )
							{
								fdata = va_arg(ap, double);
								memset(buf,0,sizeof(buf));
								int preci =1; 
								ftoa(fdata, buf, preci);
								for (str=buf ;*str!='\0'; str++) 
								{
									putchar(*str);
								}
								++format;
							}
						}
						break;
			case	'b':
						value=va_arg(ap,const int);
						memset(buf,0,sizeof(buf));
						itoa(value, buf, 2);
						for (str=buf ;*str!='\0'; str++) 
						{
							putchar(*str);
						}
						++format;
						break;
		

			default	:	
						break;
		
		}

		

	}
	
	va_end(ap);

	return 0;
}



const double eps = 1e-12;
 
char s[30];
 
void reverse(char *s)
{
     int i , j;
     int len = strlen(s);
     for( i = 0 , j = len - 1 ; i < j ; i++ , j--)
         s[i]^=s[j]^=s[i]^=s[j];
}
 
/* ftoa:   convert double n to string s with digits*/
void ftoa(double n, char *s,  int  digits)
{
     memset(s , 0 , sizeof(s));
     int i = 0 , p;
     bool sign = true;
     if( n < 0 ) 
     { 
         sign = false;
         n = -n;
     }
     long   t = ( long)n;
     n = n - t;
     if( t == 0)
     {
         s[i++] = '0';
     }
     else
     {
         while( t != 0 )
         {
             p = t % 10;
             t /= 10;
             s[i++] = p + '0';
         }
         if(!sign) s[i++] = '-';
         reverse(s);
     }
     if( fabs( n - 0.0 ) > eps )
     {
         s[i++] = '.';
         int cur_d = 0;
         while( cur_d < digits)
         {
             cur_d++;
             n *= 10.0;
             p = (long )n;
             n = n - p;
             s[i++] = p + '0';
         }
     }
     s[i] = '\0';
}