strlen causing some issues

For some reason when I try to compile this program strange things are happening like the file name is changed to "string.h". Any ideas?

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

int main()

{
    char str1[20] = "Hello\0" ;
    char str2[20] = "everyone\0" ;
    printf("%i\n",strlen(str1)) ;
    printf("%i\n",strcmp(str2)) ;
    return 0;
}