Program to find the kth character after decrypting a string in C++

In this tutorial, we will be discussing a program to find the kth character after decrypting a string.

For this, we will be provided with a string that will consist of characters and numbers and integer K. Our task is to decrypt the given string and find the character at Kth position.

Example

 Live Demo

#include <cstdlib> #include <iostream> using namespace std; //finding decrypted Kth character char findKthChar(string s, int k) {    int len = s.length();    int i = 0;    int total_len = 0;    while (i < len) {       if (isalpha(s[i])) {          total_len++;          if (total_len == k)             return s[i];          i++;       }       else {          int n = 0;          while (i < len && !isalpha(s[i])) {             n = n * 10 + (s[i] - '0');             i++;          }          int next_total_len = total_len * n;          if (k <= next_total_len) {             int pos = k % total_len;             if (!pos) {                pos = total_len;             }             return findKthChar(s, pos);          }          else {             total_len = next_total_len;          }       }    }    return -1; } int main() {    string s = "ab2c3";    int k = 5;    cout << findKthChar(s, k);    return 0; }

Output

c