lab2

 #include <iostream>

#include <string>

#include <unordered_map>

#include <cctype>

using namespace std;

string encMono(const string& txt, const string& key) {

string res = "";

unordered_map<char, char> mp;

for (int i = 0; i < 26; i++) {

mp['a' + i] = tolower(key[i]);

mp['A' + i] = toupper(key[i]);

}

for (char ch : txt)

res += isalpha(ch) ? mp[ch] : ch;

return res;

}

string decMono(const string& txt, const string& key) {

string res = "";

unordered_map<char, char> mp;

for (int i = 0; i < 26; i++) {

mp[tolower(key[i])] = 'a' + i;

mp[toupper(key[i])] = 'A' + i;

}

for (char ch : txt)

res += isalpha(ch) ? mp[ch] : ch;

return res;

}

bool validKey(const string& key) {

if (key.size() != 26) return false;

bool seen[26] = {false};

for (char ch : key) {

if (!isalpha(ch)) return false;

int idx = tolower(ch) - 'a';

if (seen[idx]) return false;

seen[idx] = true;

}

return true;

}

int main() {

string txt, key,enc;

int opt;

cout << "Enter 26-le er key: ";

getline(cin, key);

if (!validKey(key)) {

cout << "Invalid key. Must be 26 unique le ers.\n";

return 1;

}

cout << "Enter text: ";

getline(cin, txt);

enc=encMono(txt, key);

cout << "Encrypted: " << enc << endl;

cout << "Decrypted: " << decMono(enc, key) << endl;

return 0;

}

Comments

Post a Comment

Popular posts from this blog

lab1

#include <iostream> #include <string> using namespace std; string caesarEncrypt(string text, int shi ) { string result = ""; for (char c : text) { if (isalpha(c)) { char base = isupper(c) ? 'A' : 'a'; result += (char)((c - base + shi ) % 26 + base); } else { result += c; } } return result; } string caesarDecrypt(string text, int shi ) { return caesarEncrypt(text, 26 - (shi % 26)); } int main() { string inputText; int shi ; int choice; string encrypted, decrypted; cout << "=== Caesar Cipher ===\n"; cout << "Enter the text: "; getline(cin, inputText); cout << "Enter the shi value: "; cin >> shi ; encrypted = caesarEncrypt(inputText, shi ); cout << "Encrypted Text: " << encrypted << endl; decrypted = caesarDec...
Read more

lab8

 #include <iostream> #include <limits> using namespace std; void lcg(int s, int a, int c, int m, int n) {     unsigned int x = s;     for (int i = 0; i < n; i++) {         x = (a * x + c) % m;         cout << x << " ";     }     cout << endl; } int main() {     unsigned int s;     int n;     cin >> s >> n;     int a = 1664525, c = 1013904223;     unsigned int m = UINT_MAX;     lcg(s, a, c, m, n);     return 0; }
Read more

lab9

 #include<iostream> using namespace std; int g(int a, int b) {     return b == 0 ? a : g(b, a % b); } void bbs(int s, int p, int q, int n) {     int m = p * q, x = s % m;     while (n--) {         x = (x * x) % m;         cout << x << " ";     }     cout << endl; } int main() {     int s, n, p = 499, q = 547, m = p * q;     if (p % 4 != 3 || q % 4 != 3) {         cout << "p and q must be ≡ 3 mod 4\n";         return 1;     }     cout << "Enter seed (coprime with " << m << "): ";     cin >> s;     if (g(s, m) != 1) {         cout << "Seed must be coprime with " << m << endl;         return 1;     }     cout << "Enter count: ";     cin >> n; ...
Read more