Problem Copying String into Another String

[stdq]

Hello, everyone. I wrote my version of function strcpy, called strcpyUsingPoin ter, that is supposed to copy parameter s2 into parameter s1, and return s1. I also wrote a main function to test it:

#include <stdio.h>

/* Function prototypes: */
char *strcpyUsingPointer( char *s1, const char *s2 );

int main( void )
{
    char string1[ 6 ];
    char string2[ 6 ] = "house";
    
    printf( "string2 is %s.\n", string2 );
    
    printf( "strcpyUsingPointer( string1, string2 ) returned %s.\n",
        strcpyUsingPointer( string1, string2 ) );
    
    printf( "string1 is %s.\n", string1 );
    
    /* Successful program termination: */
    return 0;    
}

/* Copies string s2 into array s1. The value of s1 is returned: */
char *strcpyUsingPointer( char *s1, const char *s2 )
{
    int i;
    
    for ( i = 0 ; *( s2 + i ) != NULL ; i++ )
    {
        *( s1 + i ) = *( s2 + i );
    }
    
    return s1;
}

However, the output is a little unexpected, as shown in the picture attached. Why is this happening? Thanks in advance.

[stdq]

Problem solved. I forgot to append the terminating null-character ('\0') to end of s1. Thanks again.