The function memcpy () in C

Function void * memcpy (void * str1, const void * str2, size_t n) copies n characters from str2 to str1 .

Declare the function memcpy () in C

Below is the declaration for memcpy () in C:

 void * memcpy ( void * str1 , const void * str2 , size_t n ) 

Parameters

str1 - This is the pointer to the destination array, where the content to be copied, cast into a pointer of type void *.

str2 - This is the pointer to the data source to copy, cast into a pointer of type void *.

n - This is the number of bytes to be copied.

Returns the value

This function returns a pointer to the destination string, str1.

For example

The following program C illustrates the usage of memcpy () in C:

 #include #include struct { char name [ 40 ]; int age ; } person , person_copy ; int main () { char myname [] = "Nguyen Hoang Nam" ; /* su dung ham memcpy de sao chep chuoi: */ memcpy ( person . name , myname , strlen ( myname )+ 1 ); person . age = 46 ; /* su dung ham memcpy de sao chep struct: */ memcpy ( & person_copy , & person , sizeof ( person ) ); printf ( "person_copy = %s, %d n" , person_copy . name , person_copy . age ); return 0 ; } 

Compiling and running the above C program will result:

The function memcpy () in C Picture 1

According to Tutorialspoint

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