Write a program that checks if a string entered from the keyboard is an integer.

program zz1;
var s: string; // set a variable of string type
i, p: integer; // set a variable of integer type
begin
write (‘enter string’);
read (s); // enter a string from the keyboard
for i: = 1 to length (s) do // organize a loop in which we iterate over all characters from the first to the last
if (s [i] <> ‘1’) and (s [i] <> ‘2’) and (s [i] <> ‘3’) and (s [i] <> ‘4’) and ( s [i] <> ‘5’) and
(s [i] <> ‘6’) and (s [i] <> ‘7’) and (s [i] <> ‘8’) and (s [i] <> ‘9’) and (s [i] <> ‘0’) then p: = 1;
if p = 0 then write (‘the entered string is an integer’)
else write (‘the entered string is not an integer’);
end.