Memset is used to set a buffer with a specific character
for example
memset (dptr 'A' 10); // sets the first 10 character to character 'A'

#include <memory.h>
#include <stdio.h>

int main( void )
{
char buffer[] "This is a test of the memset function";

printf( "Before: sn" buffer );
memset( buffer '*' 4 );
printf( "After: sn" buffer );
}

Output
Before: This is a test of the memset function
After: **** is a test of the memset function