Decrypt-Ceaser-Cipher.cpp

// program to decrypt ceaser cipher
#include <bits/stdc++.h>
#include <string>
using namespace std;

int main()
{
    string s;
    cin >> s;
    //the most common letter in the english alphabet is e
    map<char, int> fre;
    for (int i = 0; i < s.length(); i++)
    {
        //cout<<"hah";
        fre[s[i]] += 1;
    }
    //finding the key
    auto x = max_element(fre.begin(), fre.end(), fre.value_comp());
    //cout<<"hah";
    int key;
    key = abs(int('e') - int(x->first));
    string fin;
    for (int i = 0; i < s.length(); i++)
    {
        //cout<<"gfg";
        fin[i] = char((int(s[i]) - key) % 26);
    }
    for (int i = 0; i < fin.length(); i++)
    {
        cout << fin[i];
    }
    return 0;
}