C memcpy() function

C memcpy() function - copy bytes in memory

Syntax:

void *memcpy(void *s1, const void * s2, size_t n)

The memcpy() function is used to copy n bytes from the object pointed to by s2 into the object pointed to by s1. If copying takes place between objects that overlap, the behavior is undefined.

Parameters:

Return value from memcpy()

The memcpy() function shall return s. No return value is reserved to indicate an error.

Example: memcpy() function.

The following example shows the usage of memcpy() function.

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

char str1[9] = "AAABBCCD";

int main( void )
{
   printf( "Original string: %s\n", str1 );
   memcpy( str1 + 3, str1, 5 );
   printf( "New string: %s\n", str1 );
}

Output:

Original string: AAABBCCD
New string: AAAAAABB

Example that uses memcpy() function

Following example copies the contents of source to target.

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

 
#define MAX_LEN 80
 
char str1[ MAX_LEN ] = "This is the string1";
char str2[ MAX_LEN ] = "This is the string2";
 
int main(void)
{
  printf("Before memcpy, strings are:");
  printf("\n%s",str1);
  printf("\n%s",str2);  
  memcpy(str2, str1, sizeof(str1));
  printf( "\n\nAfter memcpy, strings are:");
  printf("\n%s",str1);
  printf("\n%s",str2);  
}

Output:

Before memcpy, strings are:
This is the string1
This is the string2

After memcpy, strings are:
This is the string1
This is the string1

C Programming Code Editor:

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