Caesar Cipher Hackerrank.cpp

#include <bits/stdc++.h>

using namespace std;

string ltrim(const string &);
string rtrim(const string &);

/*
 * Complete the 'caesarCipher' function below.
 *
 * The function is expected to return a STRING.
 * The function accepts following parameters:
 *  1. STRING s
 *  2. INTEGER k
 */

string caesarCipher(string s, int k) {
    k=k%26;
    for(int i=0;i<s.size();i++){
        if((s[i]>='a' && s[i]<='z') || (s[i]>='A' && s[i]<='Z')){
            char a,z;
            if(s[i]>='A' && s[i]<='Z'){
                a='A';
                z='Z';
            }else{
                a='a';
                z='z';
            }
            if(s[i]+k>z){
                s[i]=a+((s[i]+k)%z)-1;
            }else{
                s[i]+=k;
            }
        }
    }
    return s;
}

int main()
{
    ofstream fout(getenv("OUTPUT_PATH"));

    string n_temp;
    getline(cin, n_temp);

    int n = stoi(ltrim(rtrim(n_temp)));

    string s;
    getline(cin, s);

    string k_temp;
    getline(cin, k_temp);

    int k = stoi(ltrim(rtrim(k_temp)));

    string result = caesarCipher(s, k);

    fout << result << "\n";

    fout.close();

    return 0;
}

string ltrim(const string &str) {
    string s(str);

    s.erase(
        s.begin(),
        find_if(s.begin(), s.end(), not1(ptr_fun<int, int>(isspace)))
    );

    return s;
}

string rtrim(const string &str) {
    string s(str);

    s.erase(
        find_if(s.rbegin(), s.rend(), not1(ptr_fun<int, int>(isspace))).base(),
        s.end()
    );

    return s;
}