ASCII 非打印字符

// yyy.cpp : Defines the entry point for the console application.
//


#include "stdafx.h"
#include <stdio.h>
#include<stdlib.h>
#include <string.h>    
#include <malloc.h>  
#define MAX_MESSAGE_LENGTH 1000
char matchStr1[]="111,aaa,ddd";  
 static char * NoPrinttoQuestionMark(char *src)
 {
     char *p = src;
     char dest[MAX_MESSAGE_LENGTH + 1024];
     memset(dest,0,sizeof(dest));
     char *q = dest;
     int dst_len = sizeof (dest);
             while(0 != *p && dst_len > 2)
             {
                 if(*p >0x1F)
                 {
                     *q++ = *p++;
                 } else {
                         *q++ = '?';
                         p++;
                 }
                 dst_len--;
             }
             *q = 0;
  return dest;
 }  
 
int main(int argc, char* argv[])
{

    char * abc="333 333 aaa aaa ddd 444 aaa 666"; 
    printf("--原先--
%s,size=%d
",abc,strlen(abc)); 
    
    abc=NoPrinttoQuestionMark(abc); 
    printf("--替换完之后--
%s,size=%d
",abc,strlen(abc));      
    return 0;
}