C++ :

#include<iostream>
#include<cstring>
#include<cstdio>
#include<cmath>
using namespace std;
int main()
{
	int n;
	char a[100];
	cin>>n;
	if(n<0)cout<<'-';	
	sprintf(a,"%d",n);
	int len=strlen(a);
	int b=0;
	if(n<0)b=1;	
	while((a[len-1]=='0')&&(len>b))len--;
	for(int i=len-1;i>=b;i--)cout<<a[i];
	cout<<endl;
	return 0;
}

Pascal :

var
st:string;
t:char;
flag:boolean;
len,i:longint;
begin
readln(st);
if st[1] = '-' then
begin
flag:=true;
delete(st,1,1);
end
else flag := false;
len := length(st);
for i := 1 to len div 2 do
begin
t := st[i];
st[i] := st[len - i + 1];
st[len - i + 1] := t;
end;
while (st[1] = '0') and (length(st) > 1) do delete(st,1,1);
if flag then st := '-' + st;
writeln(st);
end.