Caesar Cipher

/*
Made for Jonas and Callum by their favourite
Compiled using g++ under Debian GNU/Linux
*/

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

#define PUSH 3

using namespace std;

int main()
{
    string Input = "string Input";
    cout << "Please enter your sentence: \n>";
    getline(cin,Input);

    char Buffer[1024];
    char Output[1024];
    strcpy(Buffer,Input.c_str());

    for (int i = 0; i < Input.length(); i++)
    {
    Buffer[i] = tolower(Buffer[i]); //you're getting lowercase
    if (Buffer[i] < 61) Output[i] = Buffer[i];
    else if (Buffer[i] > 122 - PUSH) Output[i] = Buffer[i] + PUSH - 26;
    else Output[i] = Buffer[i] += PUSH;
    }
    cout << "\nYour 'encrypted' string is: ";
    for(int i = 0; i <= Input.length(); i++) cout << Output[i];
    cout << endl;
    return 0;
}