Ohyung Blog

| 태그 'string'에 해당되는 글 1건 |

Tech - https://ohyung.net/591 (YMD: 09/03/29 23:42)

이전 교육 받을때 구현해본 strcpy 와 strncpy...
좀더 최적화를 했더라면 하는 아쉬움이 남지만...

string 헤더 안쓰고 구현 해본다는데 목적이 있었음.
Code Type : C

        
          
          
              
              /*******************************************************************************
 * Project Name :
 *
 * Version : 1.0
 * Copyright (c) 2009 : Ohyung ( ohyung@ohyung.com )
 * Last modified at : 2009.01.23
 * *****************************************************************************/
 
 
/*******************************************************************************
 *                Include
 ******************************************************************************/
#include "stdio.h"
#include "stdlib.h"
 
 
/*******************************************************************************
 *                Define
 ******************************************************************************/
 
#define PRINTLINE() printf("--------------------------------------------------\n");
 
 
/*******************************************************************************
 *                Code
 ******************************************************************************/
void myprint(char* buff, int max)
{
    int i = 0;
    while(max)
    {
        printf("%c",buff[i++]);
        max--;
    }
    printf("\n");
}
 
#include "string.h"
// mystrcpy
// char* strcpy(char* dest, const char* src);
 
char* mystrcpy(char* dest, const char* src)
{
   int i = 0;
   while (src[i] != '\0')
   {
      dest[i] = src[i];
      i++;
   }
   dest[i] = '\0';
 
    return &dest[0];
}
 
char* mystrncpy(char* dest, const char* src, size_t maxlen)
{
   int i = 0;
   while (src[i] != '\0' && i < maxlen)
   {
      dest[i] = src[i];
      i++;
   }
   while(i < maxlen)
   {
       dest[i] = '\0';
       i++;
   }
 
    return &dest[0];
}
 
int main(void)
{
    char buff_a[50] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
    char buff_b[20] = "abcdefghijklmnopq";
 
    char buff_at[50] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
    char buff_bt[20] = "abcdefghijklmnopq";
 
    char* result = 0;
 
    printf("origin a : %s \n", buff_a);
    printf("origin b : %s \n", buff_b);
    printf("origin &a or &c : %X , %X \n", &buff_a, &buff_b);
    //printf("origin sizeof(a): %d  sizeof(b): %d \n", sizeof(buff_a), sizeof(buff_b));
 
    PRINTLINE();
    result = strcpy(buff_a, buff_b);
    printf("a : %s \n", buff_a);
    printf("b : %s \n", buff_b);
    printf("&a: %X \n", result);
    memcpy(buff_a, buff_at, strlen(buff_a));
    memcpy(buff_b, buff_bt, strlen(buff_b));
 
    PRINTLINE();
    result = mystrcpy(buff_a, buff_b);
    printf("a : %s \n", buff_a);
    printf("b : %s \n", buff_b);
    printf("&a: %X \n", result);
    memcpy(buff_a, buff_at, strlen(buff_a));
    memcpy(buff_b, buff_bt, strlen(buff_b));
 
    PRINTLINE();
    result = strncpy(buff_a, buff_b, 30);
    printf("a : %s \n", buff_a);
    printf("b : %s \n", buff_b);
    printf("&a: %X \n", result);
    myprint(buff_a, 50);
    memcpy(buff_a, buff_at, strlen(buff_a));
    memcpy(buff_b, buff_bt, strlen(buff_b));
 
 
    PRINTLINE();
    result = mystrncpy(buff_a, buff_b, 30);
    printf("a : %s \n", buff_a);
    printf("b : %s \n", buff_b);
    printf("&a: %X \n", result);
    myprint(buff_a, 50);
 
   return 0;
}
#endif

            

        
      