Unit4.12a pas

program demonstrate_strings_files;
var FirstString,SecondString:string;
input_file,output_file:text;
begin

assign(input_file,'u412a.txt');
reset(input_file);

assign(output_file,'u412a.out');
rewrite(output_file);

readln(input_file,FirstString);
readln(input_file,SecondString);

write(output_file,SecondString);
write(output_file,' ');
write(output_file,FirstString);
writeln(output_file);
close(output_file);

end.