簡單實現C語言中有幾個string相關的function。
part 1 - strcpy (string copy)
Function Name : strcpy
Definition : Copies the C string pointed by source into the array pointed by destination, including the terminating null character and stopping at that point.
Prototype : char *strcpy ( char *destination, const char *source );
#include <stdio.h>
char *strcpy_imp ( char *dest , const char *src )
{
if((dest == NULL) || (src == NULL))
{
printf("[%d %s] Input string is invalid.\n",__LINE__,__FUNCTION__);
return NULL;
}
char *ret_ptr = dest;
while(( *dest++ = *src++ ) != '\0');
return ret_ptr;
}
int main()
{
char s1[30] = "string1";
char *s2 = "abc";
printf("result = %s\n",strcpy_imp(s1,s2));
return 0;
}
Result :
sh-4.2$ gcc -o main *.c
sh-4.2$ main
result = abc