memcpy

参考： https://www.tutorialspoint.com/c_standard_library/c_function_memcpy.htm

声明：

void *memcpy(void *str1, const void *str2, size_t n)
/*1. str1 − This is pointer to the destination array
 where the content is to be copied, type-casted to a pointer of type void*.
*2.This is pointer to the source of data to be copied, 
type-casted to a pointer of type void*
3. n − This is the number of bytes to be copied. 
*/

Example:

#include <stdio.h>
#include <string.h>

int main () {
   const char src[50] = "http://www.tutorialspoint.com";
   char dest[50];
   strcpy(dest,"Heloooo!!");
   printf("Before memcpy dest = %s
", dest);
   memcpy(dest, src, strlen(src)+1);
   printf("After memcpy dest = %s
", dest);
   
   return(0);
}

Output: 

/*Before memcpy dest = Heloooo!!
After memcpy dest = http://www.tutorialspoint.com
*/